Income Taxes (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Loss Carryforwards [Line Items]
Total income tax provision	$ (1,260)	$ 2,010	$ 1,938	$ 1,844	$ (4,051)	$ 1,593	$ 2,539	$ 1,954	$ 971	$ 3,723	$ 2,067	$ 1,041	$ 4,532	$ 2,035	$ 7,802
Effective income tax rate													(7.00%)	(4.60%)	(13.60%)
Unremitted earnings													$ 181,002
Unrecognized deferred tax liability	21,210												21,210
Tax benefit from revalue of deferred tax liabilities														$ 1,524
Adjustment to valuation allowance														$ 1,524
Deferred income tax assets	57,782												57,782
Net operating loss carryforwards	369,516												369,516
Loss carryforwards for U.S. federal income tax purposes	194,962												194,962
Loss carryforwards for U.S. state income tax purposes	139,691												139,691
Loss carryforwards for foreign income tax purposes	36,894												36,894
Unrecognized tax benefits, period decrease													857
Unrecognized tax benefits, period increase													3,293
Unrecognized tax benefits that would impact effective tax rate	4,920												$ 4,920
Domestic Tax Authority
Operating Loss Carryforwards [Line Items]
Difference in effective rate due to Tax Act (as a percentage)													0.280	0.256	0.486
Research and experimentation tax credit carryforwards	2,934												$ 2,934
Foreign tax credits	4,026												4,026
State and Local Jurisdiction
Operating Loss Carryforwards [Line Items]
Research and experimentation tax credit carryforwards	4,037												4,037
Foreign Tax Authority
Operating Loss Carryforwards [Line Items]
Research and experimentation tax credit carryforwards	1,021												1,021
Other State Income Tax
Operating Loss Carryforwards [Line Items]
Other tax credits	$ 729												$ 729