Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Line Items]
Tax loss carryforwards	$ 23,100
Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Total deferred tax assets	57,903	$ 70,431
Total deferred tax liabilities	21,800	25,334
Net deferred tax asset	36,103	45,097
Non-U.S. [Member]
Income Tax Disclosure [Line Items]
Total deferred tax assets	23,723	16,575
Total deferred tax liabilities	4,750	2,597
Net deferred tax asset	18,973	13,978
Noncurrent Assets [Member] | Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Accounts receivable	686	557
Inventories	442	1,109
Deferred compensation	4,460	3,300
Depreciation and amortization
Postretirement benefits	14,759	18,286
Tax loss carryforwards	1,199	1,368
Tax credit carryforwards	30,523	41,920
Other	5,834	3,891
Deferred tax assets before valuation allowance	57,903	70,431
Less: valuation allowance
Total deferred tax assets	57,903	70,431
Noncurrent Assets [Member] | Non-U.S. [Member]
Income Tax Disclosure [Line Items]
Accounts receivable	1,224	1,341
Inventories	829	961
Deferred compensation	1,053	1,362
Depreciation and amortization	4,252	3,211
Postretirement benefits	1,667	1,464
Tax loss carryforwards	21,890	22,639
Tax credit carryforwards	1,197	1,654
Other
Deferred tax assets before valuation allowance	32,112	32,632
Less: valuation allowance	(8,389)	(16,057)
Total deferred tax assets	23,723	16,575
Noncurrent Liabilities [Member] | Domestic Tax Authority [Member]
Income Tax Disclosure [Line Items]
Unrepatriated foreign earnings	4,028	914
Depreciation and amortization	12,848	20,170
Deferred Gain	3,762	4,169
Other	1,162	81
Total deferred tax liabilities	21,800	25,334
Noncurrent Liabilities [Member] | Non-U.S. [Member]
Income Tax Disclosure [Line Items]
Unrepatriated foreign earnings
Depreciation and amortization
Deferred Gain
Other	4,750	2,597
Total deferred tax liabilities	$ 4,750	$ 2,597