Income Taxes Schedule of Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income (loss) before income taxes
Domestic	$ 220,342	$ 196,750	$ 115,526
Foreign	(85,767)	(112,123)	(78,424)
Income before income taxes	134,575	84,627	37,102
Expected federal income tax provision (benefit)	47,101	29,619	12,986
Change in valuation allowance	7,991	26,640	40,402
Stock-based compensation	(1,225)	2,762	939
Foreign earnings	(22,045)	(12,584)	(33,364)
Tax credits	(777)	(7,471)	(5,257)
Uncertain tax positions, including interest and penalties	(7,637)	3,817	4,274
Change in tax rates	41,125	67	312
State income tax provision (benefit), net of federal effect	4,986	2,806	(14)
U.S. tax provision on foreign earnings	33	997	203
Domestic production activities deduction	(2,534)	(2,424)	(1,100)
Local foreign taxes	2,324	2,914	1,450
Transaction costs	2,643	0	0
Other, net	2,341	2,431	1,268
Total provision for income taxes	$ 74,326	$ 49,574	$ 22,099