Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Assets
Cash and due from banks	$ 142,502	$ 107,035
Federal funds sold	309	2,114
Interest bearing deposits in banks	329,636	576,469
Total cash and cash equivalents	472,447	685,618
Investment securities:
Available-for-sale	2,016,864	1,786,335
Held-to-maturity (estimated fair values of $161,877 and $146,508 at December 31, 2011 and 2010, respectively)	152,781	147,068
Total investment securities	2,169,645	1,933,403
Loans held for investment	4,133,028	4,321,501
Mortgage loans held for sale	53,521	46,408
Total loans	4,186,549	4,367,909
Less allowance for loan losses	112,581	120,480
Net loans	4,073,968	4,247,429
Premises and equipment, net of accumulated depreciation	184,771	188,138
Goodwill	183,673	183,673
Company-owned life insurance	74,880	73,056
Other real estate owned ("OREO")	37,452	33,632
Accrued interest receivable	31,974	33,628
Mortgage servicing rights, net of accumulated amortization and impairment reserve	11,555	13,191
Deferred tax asset, net	9,628	18,472
Core deposit intangibles, net of accumulated amortization	7,357	8,803
Other assets	68,177	81,927
Total assets	7,325,527	7,500,970
Deposits:
Non-interest bearing	1,271,709	1,063,869
Interest bearing	4,555,262	4,861,844
Total deposits	5,826,971	5,925,713
Securities sold under repurchase agreements	516,243	620,154
Accounts payable and accrued expenses	42,248	38,915
Accrued interest payable	8,123	13,178
Long-term debt	37,200	37,502
Other borrowed funds	7	4,991
Subordinated debentures held by subsidiary trusts	123,715	123,715
Total liabilities	6,554,507	6,764,168
Stockholders' equity:
Nonvoting noncumulative preferred stock without par value; authorized 100,000 shares; issued and outstanding 5,000 shares as of December 31, 2011 and 2010	50,000	50,000
Common stock	266,842	264,174
Retained earnings	435,144	413,253
Accumulated other comprehensive income, net	19,034	9,375
Total stockholders' equity	771,020	736,802
Total liabilities and stockholders' equity	$ 7,325,527	$ 7,500,970