Income Taxes (Details 4) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating Loss Carryforwards [Line Items]
U.S.	$ 67,276	$ 13,934	$ (28,281)
Interest and penalties recognized	200	300	200
Asset
Depreciation and amortization (a)	0	0
Operating lease liabilities (a)	22,968	14,929
Expense accruals	20,844	18,421
Inventories	2,884	4,568
Provision for receivables	4,903	1,109
Operating loss carryforwards	101,022	85,378
Foreign tax credit carryforwards	11,445	24,219
Pensions	49,641	38,766
Currency adjustments	797	462
Post-retirement benefits	340	411
Stock based compensation	6,696	6,572
Other	0	0
Subtotal	221,540	194,835
Valuation allowance	(140,615)	(127,074)	$ (137,500)
Total deferred income taxes	80,925	67,761
Liability
Depreciation and amortization (a)	78,029	57,591
Right-of-use assets (a)	23,507	15,567
Deferred revenue	4,425	3,222
Deferred financing costs	269	566
Deferred Tax Liabilities, Other	74	769
Total deferred income taxes	106,304	77,715
Deferred Tax Assets, Net, Classification [Abstract]
Deferred income tax assets	15,274	14,288
Deferred tax liabilities	40,653	24,242
Foreign Tax Credit Carryforwards, Valuation Allowance Reduction, Reduction to Deferred Tax Assets	15,500
Pension Liability, Valuation Allowance Reduction, Reduction to Deferred Tax Assets	13,000
More Than Likely Asset Will Not Be Recognized, Valuation Allowance Reduction, Reduction to Deferred Tax Assets	9,800
Foreign Currency Translation Adjustment, Valuation Allowance Reduction, Reduction to Deferred Tax Assets	3,300
Sale of Businesses Reduction of Tax Paid, Change in Capital Loss Carryforwards, Foreign Tax Credit Carryforwards, State Net Operating Loss Carryforwards, Foreign Tax Credit Carryforwards		12,500
Merger and Liquidation of Foreign Dormant Entities, Valuation Allowance Reduction, Reduction to Deferred Tax Assets		5,600
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount		$ 7,900
Domestic Tax Authority [Member]
Operating Loss Carryforwards [Line Items]
Operating loss carryforwards not subject to expiration	6,300
Asset
Operating loss carryforwards	8,100
Domestic Tax Authority [Member] | Tax Years 2021 Through 2040 [Member]
Asset
Operating loss carryforwards	1,800
International operations
Operating Loss Carryforwards [Line Items]
Operating losses subject to expiration	10,500
Operating loss carryforwards not subject to expiration	65,300
Asset
Operating loss carryforwards	75,800
U.S. state
Asset
Operating loss carryforwards	17,100
U.S. state | Tax Years 2021 Through 2025 [Member]
Asset
Operating loss carryforwards	3,700
U.S. state | Tax Years 2026 Through 2030 [Member]
Asset
Operating loss carryforwards	4,000
U.S. state | Tax Years 2031 Through 2035 [Member]
Asset
Operating loss carryforwards	3,200
U.S. state | Tax Years 2036 Through 2040 [Member]
Asset
Operating loss carryforwards	$ 6,200