Income Taxes (Income Tax Expense Difference) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Tax expense at Federal statutory income tax rate	$ 23,224	$ 46,529	$ 28,798
International tax rate differential	826	(9,603)	(2,260)
Foreign source income, net of tax credits (excluding U.S. Tax Reform)	(197)	1,087	1,215
State tax, net of federal	121	279	(200)
Unrecognized tax benefits	(869)	2,874	(5,555)
U.S. Tax Reform	209	13,683	0
Equity compensation excess tax deductions	(2,238)	(3,867)	0
General business credits	(2,172)	(1,080)	(1,125)
Distribution related foreign taxes	1,916	2,173	12,433
Valuation allowance change (excluding U.S. Tax Reform)	602	1,393	171
Other	1,516	(1,002)	520
Total	$ 22,938	$ 52,466	$ 33,997