Income Taxes - Components of Income Tax Expense (Benefit) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current expense (benefit):
Federal									$ 1,316	$ (747)	$ 5,350
State									768	333	1,014
Foreign									2,644	2,324	995
Total current expense									4,728	1,910	7,359
Deferred expense (benefit):
Federal									4,078	1,089	871
State									(119)	278	(343)
Foreign									(89)	(8)	21
Total deferred expense									3,870	1,359	549
Total income tax expense	$ 3,680	$ 2,489	$ 1,366	$ 1,063	$ 1,642	$ 833	$ 1,253	$ (459)	$ 8,598	$ 3,269	$ 7,908