Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Assets
Cash and due from banks	$ 147,894	$ 141,663
Federal funds sold	543	672
Interest bearing deposits in banks	650,233	392,492
Total cash and cash equivalents	798,670	534,827
Investment securities:
Available-for-sale	1,711,924	1,947,706
Held-to-maturity (estimated fair values of $584,533 and $205,926 at December 31, 2014 and 2013, respectively)	575,186	203,837
Total investment securities	2,287,110	2,151,543
Loans held for investment	4,856,615	4,303,992
Mortgage loans held for sale	40,828	40,861
Total loans	4,897,443	4,344,853
Less allowance for loan losses	74,200	85,339
Net loans	4,823,243	4,259,514
Premises and equipment, net of accumulated depreciation	195,212	179,690
Goodwill	205,574	183,673
Company-owned life insurance	153,821	122,175
Other real estate owned (“OREO”)	13,554	15,504
Accrued interest receivable	27,063	26,450
Mortgage servicing rights, net of accumulated amortization and impairment reserve	14,038	13,546
Deferred tax asset, net	4,874	12,154
Core deposit intangibles, net of accumulated amortization	13,282	4,519
Other assets	73,495	61,056
Total assets	8,609,936	7,564,651
Deposits:
Non-interest bearing	1,791,364	1,491,683
Interest bearing	5,214,848	4,642,067
Total deposits	7,006,212	6,133,750
Securities sold under repurchase agreements	502,250	457,437
Accounts payable and accrued expenses	66,164	47,523
Accrued interest payable	5,833	4,963
Long-term debt	38,067	36,917
Other borrowed funds	9	3
Subordinated debentures held by subsidiary trusts	82,477	82,477
Total liabilities	7,701,012	6,763,070
Stockholders’ equity:
Nonvoting noncumulative preferred stock without par value; authorized 100,000 shares; no shares issued or outstanding as of December 31, 2014 and 2013	0	0
Common stock	323,596	285,535
Retained earnings	587,862	532,087
Accumulated other comprehensive loss, net	(2,534)	(16,041)
Total stockholders’ equity	908,924	801,581
Total liabilities and stockholders’ equity	$ 8,609,936	$ 7,564,651