Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	6 Months Ended		12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2010
Cash Flows From Operating Activities
Net income	$ 48,929	$ 33,449
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation	5,008	5,112
Amortization and impairment of other intangible assets	3,932	3,762
Net premium amortization on investment securities	7,439	4,242
Accretion of FDIC indemnification asset	(759)	0
Stock compensation expense	1,344	1,539
Provision for loan losses	2,449	6,519
Net securities gains	(7,611)	(2,165)
Impairment on available-for-sale securities	876	499	1,409	3,927
Gain on sale leasebacks	(3,213)	(3,273)
Gain on derivatives	(431)	(553)
Net (gains) losses on sales and write-downs of loans and other assets	301	(879)
Increase in cash surrender value of company owned life insurance	(2,983)	(2,443)
Residential real estate loans originated for sale	(30,118)	(51,273)
Proceeds from sale of residential real estate loans	30,654	56,524
Decrease in interest receivable	638	2,175
Decrease in other real estate owned	4,627	4,705
(Increase) decrease in other assets	(17,794)	8,263
Increase in accrued expenses and other liabilities	81,690	47,072
Total adjustments	76,049	79,826
Net cash flows provided by operating activities	124,978	113,275
Cash Flows From Investing Activities
Cash and cash equivalents of acquired banks	0	83,604
Purchases of investment securities available-for-sale	(546,146)	(446,971)
Purchase of trust assets	0	(1,301)
Proceeds from the call/repurchase of FHLB stock	0	14,587
Proceeds from maturities, prepayments and calls of investment securities available-for-sale	340,782	282,800
Proceeds from sales of investment securities available-for-sale	80,176	91,372
Proceeds from maturities, prepayments and calls of investment securities held-to-maturity	18,541	73,936
Proceeds from sale of loans	2,242	4,743
Reimbursements under FDIC loss share agreements	32,433	0
Net principal collected from loan customers	43,582	59,766
Proceeds from sale of premises and equipment and other assets	3,434	342
Purchases of premises and equipment and other assets	(5,061)	(2,552)
Net cash flows provided by (used in) investing activities	(30,017)	160,326
Cash Flows From Financing Activities
Deposits	58,710	(101,899)
Short-term borrowings	(78,849)	(55,556)
Payments for maturities on other borrowings	(1,072)	(403)
Payments related to retirement of debt	(16,000)	(18,333)
Cash dividends paid on common stock	(17,023)	(13,263)
Common stock repurchased	(686)	(333)
Proceeds from exercise of stock options, including tax benefit	10	140
Common stock issued	123	111
Net cash flows used in financing activities	(54,787)	(189,536)
Net increase in cash and cash equivalents	40,174	84,065
Cash and cash equivalents at beginning of period	222,872	251,552	251,552
Cash and cash equivalents at end of period	263,046	335,617	222,872	251,552
Supplemental cash flow information:
Total interest paid	20,602	30,007
Total taxes paid (net of refunds)	$ 6,369	$ 4,605