Income Taxes Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Income Tax Disclosure [Abstract]
Income tax expense	$ 960	$ 2,148	$ 3,482	$ 3,225
Effective income tax rate, percent	18.30%	37.50%	20.90%	33.90%