Income Taxes - Income Tax Expense (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current taxes:
Domestic	$ 16,036	$ 8,424	$ 4,982
Foreign	254		6
Current income tax expense	16,290	8,424	4,988
Deferred taxes:
Domestic	1,656	2,238	2,347
Foreign	(100)	(371)	(347)
Deferred income tax expense	1,556	1,867	2,000
Provision for income taxes	17,846	10,291	6,988
Income before income taxes
Domestic	50,692	27,984	19,954
Foreign	(1,585)	(1,721)	(1,767)
Income before income taxes	$ 49,107	$ 26,263	$ 18,187
Effective income tax rate (as a percent)	36.30%	39.10%	38.40%