Income Taxes (Details 4) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Asset
Depreciation and amortization	$ 6,616	$ 0
Expense accruals	17,690	23,300
Inventories	4,390	6,611
Provision for receivables	649	1,015
Operating loss carryforwards	90,193	80,178
Foreign tax credit carryforwards	27,256	26,347
Capital loss carryforwards	11,011	18,163
Pensions	47,153	74,506
Currency adjustments	7,160	17,597
Post-retirement benefits	403	760
Stock based compensation	4,761	5,812
Other	7,684	7,206
Subtotal	224,966	261,495
Valuation allowance	(174,227)	(146,097)
Total deferred income taxes	50,739	115,398
Liability
Depreciation and amortization	0	10,089
Deferred revenue	979	1,852
Deferred financing costs	2,135	0
Total deferred income taxes	3,114	11,941
Deferred Tax Assets, Net, Classification [Abstract]
Deferred income tax assets	51,574	106,311
Other liabilities	$ 3,949	$ 2,854