Accrued Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Payables and Accruals [Abstract]
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