Income Taxes (Schedule of Components of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Current:
Domestic	$ 26,713	$ 11,958	$ 13,293
Foreign	6,222	5,491	4,614
State	3,789	2,075	2,947
Provision for current income tax expense (benefit)	36,724	19,524	20,854
Deferred:
Domestic	1,711	1,580	3,481
Foreign	(155)	934	(718)
State	(228)	106	41
Provision for deferred income tax expense (benefit)	1,328	2,620	2,804
Total income taxes	$ 38,052	$ 22,144	$ 23,658