Income Taxes (Income Tax Expense (Benefit) in the Consolidated Statements of Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current
Domestic	$ 7,535	$ 2,078	$ 993
International	27,418	24,537	15,192
Total	34,953	26,615	16,185
Deferred
Domestic	21,936	3,376	4,272
International	(4,423)	4,006	(604)
Total	17,513	7,382	3,668
Domestic	29,471	5,454	5,265
International	22,995	28,543	14,588
Total	$ 52,466	$ 33,997	$ 19,853