Consolidated Balance Sheets (Unaudited) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Assets
Cash and due from banks	$ 146,577	$ 142,502
Federal funds sold	2,854	309
Interest bearing deposits in banks	387,222	329,636
Total cash and cash equivalents	536,653	472,447
Investment securities:
Available-for-sale	1,913,983	2,016,864
Held-to-maturity (estimated fair values of $166,932 and $161,877 at March 31, 2012 and December 31, 2011, respectively)	166,926	152,781
Total investment securities	2,080,909	2,169,645
Loans held for investment	4,093,815	4,133,028
Mortgage loans held for sale	76,148	53,521
Total loans	4,169,963	4,186,549
Less allowance for loan losses	102,794	112,581
Net loans	4,067,169	4,073,968
Premises and equipment, net of accumulated depreciation	187,367	184,771
Goodwill	183,673	183,673
Company-owned life insurance	75,849	74,880
Other real estate owned (OREO)	53,817	37,452
Accrued interest receivable	30,936	31,974
Mortgage servicing rights, net of accumulated amortization and impairment reserve	11,985	11,555
Deferred tax asset, net	5,017	9,628
Core deposit intangibles, net of accumulated amortization	6,647	7,357
Other assets	65,154	68,177
Total assets	7,305,176	7,325,527
Deposits:
Non-interest bearing	1,337,777	1,271,709
Interest bearing	4,563,602	4,555,262
Total deposits	5,901,379	5,826,971
Securities sold under repurchase agreements	455,993	516,243
Accounts payable and accrued expenses	33,589	42,248
Accrued interest payable	8,215	8,123
Long-term debt	37,181	37,200
Other borrowed funds	7	7
Subordinated debentures held by subsidiary trusts	82,477	123,715
Total liabilities	6,518,841	6,554,507
Stockholders' equity:
Nonvoting noncumulative preferred stock without par value; authorized 100,000 shares; issued and outstanding 5,000 shares as of March 31, 2012 and December 31, 2011	50,000	50,000
Common stock	269,698	266,842
Retained earnings	448,372	435,144
Accumulated other comprehensive income, net	18,265	19,034
Total stockholders' equity	786,335	771,020
Total liabilities and stockholders' equity	$ 7,305,176	$ 7,325,527