Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating Loss Carryforwards [Line Items]
Net increase (decrease) in deferred tax asset valuation allowance	$ (6,300)	$ 28,600
Aggregate tax loss carryforward	8,500
Valuation allowance of deferred tax assets	113,237	119,494
Deferred tax assets related to U.S. federal tax carryforwards	46,600	48,600
Deferred tax assets related to U.S. state tax carryforwards	11,100	12,500
Deferred tax assets related to foreign tax carryforwards	47,700	49,900
Net benefit related to increase in unrecognized tax benefits	1,700
Income tax penalties and interest	200	200	$ 200
Interest from settlements, lapse of statutes, and change in certainty released	200
Cumulative accrued balance of penalties and interest	600	700	600
Unrecognized tax benefits that would impact effective tax rate	4,500	6,200	$ 4,800
Valuation Allowance Related To Income Tax Expense
Operating Loss Carryforwards [Line Items]
Net increase (decrease) in deferred tax asset valuation allowance	5,300	24,400
Impact of Unrecorded Tax Attributes Related to Changes in Cumulative Translation Adjustments
Operating Loss Carryforwards [Line Items]
Net increase (decrease) in deferred tax asset valuation allowance	$ 1,000	$ 4,200