Income Taxes (Components of Income Tax Provision) (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	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, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Current:
U.S. federal													$ (5,882)	$ (83)	$ (2,110)
State													286	741	30
Foreign													10,621	12,711	8,099
Total													5,025	13,369	6,019
Deferred:
U.S. federal													(322)	0	(1,245)
State													3	1,097	0
Foreign													(2,671)	(6,664)	(5,321)
Total													(2,990)	(5,567)	(6,566)
Total income tax provision (benefit)	$ (4,051)	$ 1,593	$ 2,539	$ 1,954	$ 971	$ 3,723	$ 2,067	$ 1,041	$ (1,212)	$ (2,214)	$ 1,700	$ 1,179	$ 2,035	$ 7,802	$ (547)