Income Taxes (Deferred Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Deferred employee benefits	$ 82,836	$ 83,390
Inventories	9,694	9,410
Tax loss and credit carryforwards	19,216	19,529
Accrued liabilities and other items	12,433	12,491
Total deferred tax assets	124,179	124,820
Deferred tax liabilities:
Property, plant and equipment	(15,653)	(17,178)
Intangibles	(48,785)	(42,717)
Other items	(3,100)	(2,195)
Total deferred tax liabilities	(67,538)	(62,090)
Net deferred tax assets before valuation allowance	56,641	62,730
Valuation allowance	(4,143)	(11,122)
Net deferred tax assets after valuation allowance	52,498	51,608
Change in valuation allowance	7,000
Pre-tax income (loss) from foreign operations	(5,000)	$ (4,300)	$ (2,300)
Undistributed earnings from foreign subsidiaries	29,900
Delamac
Deferred tax liabilities:
Net deferred tax assets	$ 2,700