Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010
Operating Activities
Net cash provided by operating activities	$ 135,267	$ 96,450
Investing Activities
Proceeds from sales, maturities and prepayments of investments available-for-sale	429,256	244,484
Purchases of investments available-for-sale	(796,155)	(469,030)
Principal collected on loans	459,488	427,901
Loans originated or acquired	(397,174)	(416,715)
Net decrease (increase) of non-marketable equity securities	14,278	(1,729)
Proceeds from sale of other real estate owned	17,443	25,722
Net addition of premises and equipment and other real estate owned	(7,337)	(9,003)
Net cash used in investment activities	(280,201)	(198,370)
Financing Activities
Net increase in deposits	182,897	409,964
Net decrease in Federal Home Loan Bank advances	(40,080)	(260,385)
Net increase in securities sold under repurchase agreements	1,900	11,891
Net decrease in Federal Reserve Bank discount window		(225,000)
Net increase (decrease) in federal funds purchased and other borrowed funds	42,865	(3,610)
Cash dividends paid	(18,698)	(18,697)
Deficiencies in benefits related to the exercise of stock options		(4)
Proceeds from exercise of stock options and other stock issued		145,654
Net cash provided by financing activities	168,884	59,813
Net increase (decrease) in cash and cash equivalents	23,950	(42,107)
Cash and cash equivalents at beginning of period	105,091	210,575
Cash and cash equivalents at end of period	129,041	168,468
Supplemental Disclosure of Cash Flow Information
Cash paid during the period for interest	23,985	27,262
Cash paid during the period for income taxes	3,681	8,061
Sale and refinancing of other real estate owned	2,521	6,320
Other real estate acquired in settlement of loans	$ 49,570	$ 45,888