Income Taxes (Components of income tax expense and income before taxes, by jurisdiction) (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, 2019	Dec. 31, 2018	Dec. 31, 2017
Geographic sources of income (loss) before income taxes
United States									$ 1,138	$ 5,535	$ 26,040
Foreign									158,672	180,280	281,456
Income before taxes									159,810	185,815	307,496
Current:
Federal									(179)	22,003	0
State									3	39	11
Foreign									11,427	47,318	81,969
Current income tax expense (benefit)									11,251	69,360	81,980
Deferred:
Federal									1,832	5,468	(34,787)
State									299	2,993	(4,072)
Foreign									23,800	(21,571)	(3,330)
Deferred income tax expense (benefit)									25,931	(13,110)	(42,189)
Income tax expense	$ 764	$ 9,141	$ 5,897	$ 21,380	$ 28,812	$ 14,326	$ 10,631	$ 2,481	$ 37,182	$ 56,250	$ 39,791