Acquisitions (Details) - Patriot Bancshares Inc - USD ($) $ / shares in Units, $ in Thousands, shares in Millions		12 Months Ended
	Oct. 01, 2015	Dec. 31, 2015	Sep. 30, 2016	Sep. 30, 2015
ACQUISITIONS
Total assets				$ 1,400,000
Total loans				1,100,000
Total deposits				1,100,000
Total shareholders equity				$ 125,200
Number of shares issued upon merger	10.4
Value of stock issued upon merger	$ 123,700
Business Acquisition, Share Price	$ 11.85
Series B and C Preferred stock	$ 27,300
Goodwill, initial amount recognized		$ 55,162
Finite-lived Intangible Assets Acquired		$ 8,261
Deferred tax assets, net			$ 7,300