Income Taxes (Deferred Income Taxes) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Deferred Tax Assets, Operating Loss Carryforwards, Not Subject to Expiration	$ 10,000
Deferred tax assets:
Deferred employee benefits	36,678	$ 43,118
Tax loss and credit carryforwards	19,449	17,610
Accrued liabilities and other items	14,044	9,036
Total deferred tax assets	70,171	69,764
Deferred tax liabilities:
Property, plant and equipment	(6,410)	(2,677)
Intangibles	(27,147)	(27,732)
Other items	(226)	(218)
Deferred Tax Liabilities, Gross	33,783	30,627
Net Deferred Tax Assets Before Valuation Allowance	36,388	39,137
Valuation allowance	(8,142)	(8,243)
Net deferred tax assets after valuation allowance	28,246	30,894
Pre-tax income (loss) from foreign operations	$ (4,000)	$ (27,100)	$ 1,000