Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Assets
Cash and due from banks	$ 150,085	$ 177,978
Federal funds sold	811	730
Interest bearing deposits in banks	391,447	622,624
Total cash and cash equivalents	542,343	801,332
Investment securities:
Available-for-sale	1,939,806	1,995,258
Held-to-maturity (estimated fair values of $208,482 and $218,933 at September 30, 2013 and December 31, 2012, respectively)	205,277	208,223
Total investment securities	2,145,083	2,203,481
Loans held for investment	4,279,959	4,157,470
Mortgage loans held for sale	52,133	66,442
Total loans	4,332,092	4,223,912
Less allowance for loan losses	92,990	100,511
Net loans	4,239,102	4,123,401
Premises and equipment, net of accumulated depreciation	179,785	187,565
Goodwill	183,673	183,673
Company-owned life insurance	76,701	76,729
Other real estate owned (OREO)	18,537	32,571
Accrued interest receivable	30,384	28,869
Mortgage servicing rights, net of accumulated amortization and impairment reserve	13,518	12,653
Deferred tax asset, net	11,857	2,597
Core deposit intangibles, net of accumulated amortization	4,873	5,937
Other assets	54,244	62,953
Total assets	7,500,100	7,721,761
Deposits:
Non-interest bearing	1,503,969	1,495,309
Interest bearing	4,604,656	4,745,102
Total deposits	6,108,625	6,240,411
Securities sold under repurchase agreements	428,110	505,785
Accounts payable and accrued expenses	45,523	48,208
Accrued interest payable	5,367	6,502
Long-term debt	37,128	37,160
Other borrowed funds	10	32
Preferred stock pending redemption	0	50,000
Subordinated debentures held by subsidiary trusts	82,477	82,477
Total liabilities	6,707,240	6,970,575
Stockholders' equity:
Nonvoting noncumulative preferred stock without par value; authorized 100,000 shares; no shares issued and outstanding as of September 30, 2013 and 5,000 shares issued and outstanding as of Decebmer 31, 2012	0	0
Common stock	283,352	271,335
Retained earnings	517,456	463,860
Accumulated other comprehensive income, net	(7,948)	15,991
Total stockholders' equity	792,860	751,186
Total liabilities and stockholders' equity	$ 7,500,100	$ 7,721,761