Income Taxes (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Jan. 31, 2017	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate		22.20%	24.90%
Provision for income taxes		$ 7,253	$ 7,680
Change in enacted tax rate		400
Net income		25,429	23,121	$ 69,496
Gain on bargain purchase of a business	$ 8,400	$ 0	$ 8,388