Subsequent Events (Details) - Acquisition Activity - USD ($) $ / shares in Units, $ in Thousands	Jan. 06, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Goodwill		$ 340,879	$ 319,007	$ 310,589	$ 264,062
Standard Bancshares, Inc. | Subsequent Event
Assets
Cash and due from banks and interest-bearing deposits in other banks	$ 101,944
Securities available-for-sale	214,098
FHLB and FRB stock	3,247
Loans	1,795,562
OREO	9,223
Investment in BOLI	55,629
Goodwill	328,296
Other intangible assets	25,868
Premises, furniture, and equipment	56,253
Accrued interest receivable and other assets	48,707
Total assets	2,638,827
Liabilities
Noninterest-bearing deposits	676,295
Interest-bearing deposits	1,347,760
Total deposits	2,024,055
Accrued interest payable and other liabilities	34,289
Total liabilities	$ 2,058,344
Consideration Paid
Common stock, shares issued (in shares)	21,057,085
Shares issued (in dollars per share)	$ 25.34
Common stock (21,057,085 shares issued at $25.34 per share), net of issuance costs	$ 533,358
Cash paid	47,125
Total consideration paid	$ 580,483