Acquisitions (Details) - Unaudited Pro Forma Combined Results of Operations (Details) - Standard Bancshares, Inc. - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Business Acquisition [Line Items]
Total revenues	[1]	$ 162,528	$ 154,831	$ 319,285	$ 298,176
Net income		$ 35,652	$ 29,304	$ 68,386	$ 52,465

[1] Includes net interest income and total noninterest income.