Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Assets
Cash and due from banks	$ 142,119	$ 141,663
Federal funds sold	737	672
Interest bearing deposits in banks	677,107	392,492
Total cash and cash equivalents	819,963	534,827
Investment securities:
Available-for-sale	1,586,503	1,947,706
Held-to-maturity (estimated fair values of $588,032 and $205,926 at September 30, 2014 and December 31, 2013, respectively)	583,271	203,837
Total investment securities	2,169,774	2,151,543
Loans held for investment	4,791,444	4,303,992
Mortgage loans held for sale	62,938	40,861
Total loans	4,854,382	4,344,853
Less allowance for loan losses	74,231	85,339
Net loans	4,780,151	4,259,514
Goodwill	204,646	183,673
Premises and equipment, net of accumulated depreciation	207,181	179,690
Company-owned life insurance	152,761	122,175
Other real estate owned (OREO)	18,496	15,504
Accrued interest receivable	30,282	26,450
Core deposit intangibles, net of accumulated amortization	14,137	4,519
Mortgage servicing rights, net of accumulated amortization and impairment reserve	13,894	13,546
Deferred tax asset, net	1,347	12,154
Other assets	68,720	61,056
Total assets	8,481,352	7,564,651
Deposits:
Non-interest bearing	1,637,151	1,491,683
Interest bearing	5,322,348	4,642,067
Total deposits	6,959,499	6,133,750
Securities sold under repurchase agreements	432,478	457,437
Accounts payable and accrued expenses	56,210	47,523
Accrued interest payable	5,569	4,963
Long-term debt	36,882	36,917
Other borrowed funds	1,934	3
Subordinated debentures held by subsidiary trusts	102,916	82,477
Total liabilities	7,595,488	6,763,070
Stockholders' equity:
Nonvoting noncumulative preferred stock without par value; authorized 100,000 shares; no shares issued and outstanding as of September 30, 2014 or December 31, 2013	0	0
Common stock	321,132	285,535
Retained earnings	572,362	532,087
Accumulated other comprehensive income, net	(7,630)	(16,041)
Total stockholders' equity	885,864	801,581
Total liabilities and stockholders' equity	$ 8,481,352	$ 7,564,651