Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate	27.20%	37.20%	25.40%	32.20%
Provision for income taxes	$ 16,476	$ 16,712	$ 23,729	$ 24,392
Change in enacted tax rate	(200)		700
Net income	$ 44,086	$ 28,214	$ 69,515	$ 51,335	$ 41,282