Income Taxes - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income tax expense (benefit)	$ 3,316	$ 2,947	$ 4,571	$ 5,801
Effective tax rate	30.60%	31.60%	21.70%	27.80%