Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0001027884 (http://www.sec.gov/CIK)

Compensation and Retirement Disclosure [Abstract]	Period [Axis]
	2016-01-01 - 2016-12-31
Compensation and Retirement Disclosure [Abstract]
Components of Net Periodic Benefit Cost	The following tables present combined information for our defined benefit pension and other postretirement plans: Components of Net Periodic Benefit Cost   Pension Plans   Other Postretirement Plans     2016   2015   2014   2016   2015   2014 Service cost   $ 9,337   $ 10,611   $ 9,113   $ 704   $ 791   $ 1,037 Interest cost   23,078   23,242   33,530   1,361   1,545   2,279 Expected return on plan assets   (26,314 )   (28,341 )   (36,577 )   —   —   — Amortization of prior service credits   (617 )   (620 )   (465 )   —   —   — Recognized net actuarial losses (gains)   5,719   7,648   4,649   (3,361 )   (2,696 )   (863 ) Net periodic benefit cost (income)   $ 11,203   $ 12,540   $ 10,250   $ (1,296 )   $ (360 )   $ 2,453
Change in Benefit Obligation	Change in Projected Benefit Obligation   Pension Plans   Other Postretirement Plans     2016   2015   2016   2015 Projected benefit obligation at beginning of year   $ 824,968   $ 945,522   $ 30,948   $ 51,458 Service cost   9,337   10,611   704   791 Interest cost   23,078   23,242   1,361   1,545 Actuarial loss (gain) (1)   127,406   (45,456 )   2,702   (20,863 ) Plan participants’ contributions   2,850   2,828   502   452 Benefits paid   (36,955 )   (33,521 )   (2,810 )   (2,435 ) Currency translation (2)   (73,427 )   (78,258 )   —   — Projected benefit obligation at end of year   $ 877,257   $ 824,968   $ 33,407   $ 30,948
Change in Plan Assets	Change in Plan Assets   Pension Plans   Other Postretirement Plans     2016   2015   2016   2015 Fair value of plan assets at beginning of year   $ 707,088   $ 783,219   $ —   $ — Actual return on plan assets   78,360   1,211   —   — Benefits paid   (36,955 )   (33,521 )   (2,810 )   (2,435 ) Employer contributions (3)   16,770   16,918   2,308   1,983 Plan participants’ contributions   2,850   2,828   502   452 Currency translation (2)   (65,009 )   (63,567 )   —   — Fair value of plan assets at end of year   $ 703,104   $ 707,088   $ —   $ — Funded status   $ (174,153 )   $ (117,880 )   $ (33,407 )   $ (30,948 ) Balance Sheet Position   Pension Plans   Other Postretirement Plans     2016   2015   2016   2015 Prepaid benefit cost within other non-current assets   $ 2,798   $ 13,581   $ —   $ — Accrued benefit cost within other current liabilities   (2,687 )   (2,699 )   (2,476 )   (2,432 ) Accrued benefit cost within other non-current liabilities   (174,264 )   (128,762 )   (30,931 )   (28,516 ) Net funded status recognized   $ (174,153 )   $ (117,880 )   $ (33,407 )   $ (30,948 )                   Unrecognized net prior service credits   $ (3,259 )   $ (3,975 )   $ —   $ — Unrecognized net actuarial losses (gains)   200,334   144,680   (25,508 )   (31,571 ) Accumulated other comprehensive loss (income), before taxes (4)   $ 197,075   $ 140,705   $ (25,508 )   $ (31,571 ) (1)  The actuarial pension plan loss for 2016 was primarily associated with a decrease in discount rate assumptions for our pension plans. The actuarial pension plan gain for 2015 was primarily associated with an increase in the discount rate assumptions for our pension plans. The actuarial other postretirement plan gain for 2015 was primarily associated with an increase in the discount rate assumptions and a decrease in the percent of retiring employees electing medical coverage for our other postretirement plan. (2)  The currency translation loss for 2016 and 2015 was primarily associated with the strengthening of the U.S. Dollar against the currencies associated with our international pension plans, primarily the Euro and British Pound. (3)  During 2017, we expect to contribute approximately $17,000 and $2,500 to our pension and other postretirement plans, respectively. (4)  During 2017, we expect to recognize approximately $(600) and $5,500 of previously unrecognized net prior service pension credits and net actuarial pension losses, respectively.
Defined Benefit Plans with an Accumulated Benefit Obligation in Excess of Plan Assets	The following table includes summary information for those defined benefit plans with an accumulated benefit obligation in excess of plan assets:     December 31,     2016   2015 Projected benefit obligation   $ 766,618   $ 714,539 Accumulated benefit obligation   $ 748,862   $ 713,187 Fair value of plan assets   $ 589,667   $ 583,081
Weighted-Average Assumptions Used to Measure Defined Benefit Pension and Other Postretirement Plans	The following table presents the weighted-average assumptions used to measure our defined benefit pension and other postretirement plans:     Pension Plans   Other Postretirement Plans     2016   2015   2016   2015 Weighted-average assumptions used to determine benefit obligations at December 31,                 Discount rate   2.11 %   2.95 %   4.15 %   4.47 % Rate of compensation increase (1)   2.36 %   2.37 %   n/a   n/a Weighted-average assumptions used to determine net periodic benefit cost for the years ended December 31,                 Discount rate   2.95 %   2.64 %   4.47 %   4.13 % Expected long-term rate of return on plan assets (2)   3.87 %   3.81 %   n/a   n/a Rate of compensation increase (1)   2.36 %   2.90 %   n/a   n/a (1)  The rate of compensation increase relates solely to the defined benefit plans that factor compensation increases into the valuation. (2)  The expected long-term rate of return on plan assets was derived using historical returns by asset category and expectations of future performance.
Expected Defined Benefit Pension and Other Postretirement Plan Payments	The following table includes the expected defined benefit and other postretirement plan payments for the next 10 years: Year   Pension Plans   Other Postretirement Plans 2017   $ 37,783   $ 2,476 2018   $ 33,699   $ 2,471 2019   $ 33,859   $ 2,446 2020   $ 34,584   $ 2,408 2021   $ 35,245   $ 2,337 2022-2026   $ 183,871   $ 10,820
Plan Assets at Fair Value by Investment Category and Valuation Hierarchy Level	The following tables present the fair value of our plan assets by investment category and valuation hierarchy level at December 31, 2016 and 2015:   December 31, 2016   Level 1 Level 2 Level 3 Total Asset Category Equity Securities: Global Equities and Cash $ 3,310 $ — $ — $ 3,310 International Funds (1) — 155,560 — 155,560 Emerging Markets Growth Funds — 17,342 — 17,342 U.S. Equity Funds —   13,766   —   13,766 Fixed Income Securities: International Government Bonds (2) —   180,850   —   180,850 International Corporate Bonds (3) —   110,626   —   110,626 International Mortgage Funds (4)   —   64,174   —   64,174 All Other Fixed Income Securities (5)   —   50,321   —   50,321 Other Investments:               Asset Allocation Funds (6)   —   107,155   —   107,155 Total Assets at Fair Value $ 3,310 $ 699,794 $ — $ 703,104     December 31, 2015     Level 1   Level 2   Level 3   Total Asset Category                 Equity Securities:                 Global Equities and Cash   $ 2,278   $ —   $ —   $ 2,278 International Funds (1)   —   167,695   —   167,695 U.S. Equity Funds   —   20,158   —   20,158 Emerging Markets Growth Funds   —   15,764   —   15,764 Fixed Income Securities:                 International Government Bonds (2)   —   253,969   —   253,969 International Corporate Bonds (3)   —   96,262   —   96,262 International Mortgage Funds (4)   —   21,679   —   21,679 All Other Fixed Income Securities (5)   —   47,504   —   47,504 Other Investments:                 Asset Allocation Funds (6)   —   81,779   —   81,779 Total Assets at Fair Value   $ 2,278   $ 704,810   $ —   $ 707,088 The following provides descriptions for plan asset categories with significant balances in the tables above: (1)  Investments in various funds that track international indices. (2)  Investments in predominately EU government securities and U.K. Treasury securities with credit ratings primarily AAA. (3)  Investments in European and U.K. fixed interest securities with credit ratings of primarily BBB and above. (4)  Investments in international mortgage funds. (5)  Investments predominantly in various international fixed income obligations that are individually insignificant. (6)  Investments in fixed income securities, equities and alternative asset classes, including commodities and property assets.
Additional Information Regarding Significant Multi-Employer Pension Plans	The following table provides additional information regarding our significant multi-employer defined benefit pension plans, including the funding level of each plan (or zone status, as defined by the Pension Protection Act), whether actions to improve the funding level of the plan have been implemented, where required (a funding improvement plan (“FIP”) or rehabilitation plan (“RP”), and our contributions to each plan and total contributions for 2016, 2015 and 2014, among other disclosures:     EIN/Plan Number   Plan Year End   Pension Protection Act (% Funded) (1)   FIP/RP Plan (1)   Total Company Contributions (2)   Expiration Date of Collective- Bargaining Agreement (3) Pension Fund     2016   2015   2016   2015   2014   Boilermaker-Blacksmith National Pension Trust   48-6168020-001   12/31   65%-80%   65%-80%   Yes   $ 35,235   $ 32,918   $ 33,105   Various Plumbers and Pipefitters National Pension Fund   52-6152779-001   6/30   65%-80%   65%-80%   Yes   5,443   4,712   3,895   Various Utah Pipe Trades Pension Trust Fund   51-6077569-001   12/31   >80%   >80%   No   4,321   5,522   664   07/19 Central Laborers’ Pension Fund   37-6052379-001   12/31   65%-80%   <65%   Yes   2,054   2,083   1,881   Various Twin City Carpenters and Joiners Pension Fund   41-6043137-001   12/31   65%-80%   65%-80%   Yes   1,295   5,469   6,010   04/19 Twin City Ironworkers Pension Plan   41-6084127-001   12/31   >80%   >80%   No   731   2,102   2,791   04/19 Middle Tennessee Carpenters and Millwrights Pension Fund (4)   62-6101275-001   4/30   >80%   >80%   No   —   6,809   4,729   Various Southern Ironworkers Pension Fund (4)   59-6227091-001   12/31   >80%   >80%   No   —   3,823   2,150   Various Plumbers and Steamfitters Local 150 Pension Fund (4)   58-6116699-001   12/31   >80%   >80%   No   —   3,510   2,154   Various Boilermakers’ National Pension Plan (Canada)   366708   12/31   N/A   N/A   N/A   6,709   8,645   10,795   04/19 All Other (5)                       64,621   62,120   49,913     Total                       $ 120,409   $ 137,713   $ 118,087     (1)  Pension Protection Act Zone Status and FIP/RP plans are applicable to our U.S.-registered plans only, as these terms are not defined within Canadian pension legislation. In the U.S., plans funded less than 65% are in the red zone, plans funded at least 65%, but less than 80% are in the yellow zone, and plans funded at least 80% are in the green zone. The requirement for FIP or RP plans in the U.S. is based on the funding level or zone status of the applicable plan. (2)  Our 2016 contributions as a percentage of total plan contributions were not available for any of our plans. For 2015 and 2014, our contributions to the Utah Pipe Trades Pension Trust Fund, the Twin City Carpenters and Joiners Pension Fund, the Twin City Ironworkers Pension Plan, the Southern Ironworkers Pension Fund, the Plumbers and Steamfitters Local 150 Pension Fund and the Boilermakers’ National Pension Plan (Canada) each exceeded 5% of total plan contributions. The level of our contributions to each plan noted above varies from period to period based upon the level of work being performed that is covered under the applicable collective-bargaining agreement. (3)  The expiration dates of our labor agreements associated with the plans noted as “Various” above vary based upon the duration of the applicable projects. (4)  The contributions in 2015 and 2014 were associated with plans that were included with our former Nuclear Operations, which were sold on December 31, 2015. (5)  Our remaining contributions are to various U.S. and Canadian plans, which are individually immaterial.