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

Reporting Entity [Axis]

0000819793 (http://www.sec.gov/CIK)

Payables and Accruals [Abstract]	Period [Axis]
	2016-01-01 - 2016-12-31
Payables and Accruals [Abstract]
Schedule of Accrued Liabilities	Accrued liabilities consist of:  (in thousands)   2016 2015 Salaries and wages   $18,520 $17,621 Accrual for compensated absences     10,181      9,564 Employee benefits     13,277    10,880 Pension liability - current portion       2,057      2,110 Postretirement medical benefits - current portion     4,195      4,660 Returns and allowances     13,714    14,024 Interest       1,218         942 Restructuring costs       4,668      6,856 Dividends       5,458      5,443 Workers' compensation       2,053      2,086 Billings in excess of revenue recognized       2,390      2,903 Professional fees       3,068      2,093 Utilities          991         779 Other     13,405    11,824 Total   $95,195 $91,785