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

Reporting Entity [Axis]

0001280058 (http://www.sec.gov/CIK)

Debt Disclosure [Abstract]	Period [Axis]
	2016-01-01 - 2016-12-31
Debt Disclosure [Abstract]
Summary of Debt	The following table summarizes our debt balances and the related weighted average effective interest rates, which includes the effect of interest rate swap agreements.   Debt balance at     Weighted average effective interest rate at   (dollars in thousands) December 31, 2016 December 31, 2015   December 31, 2016 December 31, 2015 Credit facility:               Revolving credit loans $ 180,900 $ 242,900   2.36 % 2.15 %     Term loans 162,969 167,344   2.62 % 2.51 %         Total debt 343,869 410,244   2.48 % 2.30 % Less: Unamortized debt discount 1,476 2,157       Less: Debt, current portion 4,375 4,375   2.50 % 2.11 % Debt, net of current portion $ 338,018 $ 403,712   2.48 % 2.30 %
Annual Maturities Related to Credit Facility	As of December 31, 2016, the required annual maturities related to the 2014 Credit Facility were as follows: Years ending December 31, (dollars in thousands) Annual maturities 2017  $ 4,375 2018  4,375 2019  335,119 2020  — 2021  — Thereafter — Total required maturities $ 343,869