Income Taxes (Details 1) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Pension	$ 27,410	$ 25,331
Tax loss carryforwards	16,686	15,330
Inventory valuation	15,518	15,938
Other postretirement/postemployment costs	14,071	15,753
Accrued Compensation	10,121	10,242
Other	6,489	5,880
Valuation allowance	(14,957)	(14,401)
Total deferred tax assets	75,338	74,073
Current deferred tax assets	0	24,825
Non-current deferred tax assets	25,433	1,139
Deferred tax liabilities:
Depreciation and amortization	89,198	81,158
Goodwill	(14,871)	(14,545)
Other	(12,282)	(16,313)
Total deferred tax liabilities	116,351	112,016
Net deferred tax liabilities	(41,013)	(37,943)
Current deferred tax liabilities (included in accrued liabilities)	0	(1,543)
Non-current deferred tax liabilities	$ (66,446)	$ (62,364)