Acquisitions - Independence Bank Acquisition (Details) - USD ($) $ / shares in Units, $ in Thousands	Jan. 26, 2015	Mar. 31, 2016	Jan. 29, 2016	Dec. 31, 2015	Mar. 31, 2015
Acquisitions
Closing stock price of common stock ($ per share)			$ 20.53
Goodwill		$ 102,085		$ 50,832	$ 51,010
IDPK
Acquisitions
Consideration paid	$ 79,777
Cash consideration for common stockholders	6,100
Cash consideration for holders of stock options and warrants	1,500
Warrants assumed	$ 1,300
Number of shares of common stock issued as consideration	4,480,645
Value of shares of common stock issued as consideration	$ 70,900
Closing stock price of common stock ($ per share)	$ 15.83
Goodwill	$ 27,882