Income Taxes (Details 2) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Deferred tax assets:
Pension	$ 16,256	$ 19,025
Tax loss carryforwards	9,167	11,516
Inventory valuation	12,251	11,576
Other postretirement/postemployment costs	8,066	8,372
Accrued Compensation	7,753	9,384
Lease obligation	9,188
Other	14,769	3,349
Valuation allowance	(3,592)	(4,366)
Total deferred tax assets	73,858	58,856
Deferred tax liabilities:
Depreciation and amortization	(110,230)	(122,636)
Goodwill	(9,757)	(9,597)
Swedish tax incentive	(7,436)	(7,241)
Right of use liability	(9,050)
Other	(4,558)	(5,467)
Total deferred tax liabilities	141,031	144,941
Non-current deferred tax assets	21,235	20,474
Non-current deferred tax liabilities	(88,408)	(106,559)
Net deferred tax liabilities	$ (67,173)	$ (86,085)