Income Taxes (Components of Deferred Income Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018		Dec. 31, 2017
Deferred income tax assets:
Pension	$ 9,722		$ 8,108
Non-pension post-retirement benefits	11,712		13,385
Other accrued liabilities	16,477		13,213
Receivables	1,994		2,118
Net operating loss and charitable contribution carry forwards	14,143	[1]	16,599
Tax credits	13,373	[2]	13,288
Total deferred income tax assets	67,421	[3]	66,711
Valuation allowances	(22,068)		(19,076)
Net deferred income tax assets	45,353		47,635
Deferred income tax liabilities:
Property, plant and equipment	15,332		18,246
Inventories	1,699		1,639
Intangibles and other	4,987		4,708
Total deferred income tax liabilities	22,018		24,593
Net deferred income tax asset	23,335		$ 23,042
U.S. AMT credits	1,300
Foreign tax credits	9,000
Future taxable income needed to realize deferred tax assets	151,900
Tax Period 2024 - 2038
Deferred income tax liabilities:
U.S. general business credits	3,000
U.S. Federal | Tax Period 2019 - 2038
Deferred income tax assets:
Net operating loss and charitable contribution carry forwards	3,900
Non-US | Tax Period 2021 - 2027
Deferred income tax assets:
Net operating loss and charitable contribution carry forwards	$ 10,200

[1] At December 31, 2018, U.S. operating loss carryforwards of $3.9 million expire between 2019 and 2038, and non-U.S. operating loss carryforwards of $10.2 million expire between 2021 and 2027.

[2] At December 31, 2018, U.S. general business credit carryforwards of $3.0 million expire between 2024 and 2038. U.S. AMT credits of $1.3 million and the foreign credits of $9.0 million do not expire.

[3] In order to fully realize our U.S. deferred tax assets as of December 31, 2018, the Company needs to generate approximately $151.9 million of future taxable income.