Acquisitions - Supplemental Pro-forma Information (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Business Combinations [Abstract]
Revenue	[1]	$ 204,172	$ 180,436	$ 400,407	$ 328,384
Income before income taxes	[1]	$ 90,743	$ 66,510	$ 163,298	$ 127,744

[1] Net interest income plus noninterest income.