Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Income Taxes
Income tax expense	$ 2,517	$ 2,101	$ 7,987	$ 2,648
Effective tax rate (as a percent)	38.70%	45.20%	41.30%	43.60%