Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Operating Activities:
Net income	$ 61,033	$ 51,928
Adjustments to reconcile net income to net cash from operating activities:
Provision for loan losses	1,100	9,450
Deferred tax expense (benefit)	(2,539)	(139)
Accretion of loan discounts	(2,962)	(2,366)
Securities premium amortization (discount accretion), net	4,539	2,368
Net (gain) loss on securities transactions	491	(5)
Depreciation and amortization	9,497	9,191
Net loss on sale/write-down of assets/foreclosed assets	477	1,597
Stock-based compensation	2,555	3,737
Net tax benefit (deficiency) from stock-based compensation	(418)	(65)
Excess tax benefits from stock-based compensation	(41)	(154)
Earnings on life insurance policies	(1,068)	(988)
Net change in:
Trading account securities	(3,237)	(5,645)
Accrued interest receivable and other assets	41,769	27,621
Accrued interest payable and other liabilities	(9,286)	(25,293)
Net cash from operating activities	101,910	71,237
Securities held to maturity:
Purchases		(57,547)
Maturities, calls and principal repayments	315	156
Securities available for sale:
Purchases	(10,984,308)	(6,195,353)
Sales	9,985,078	5,547,541
Maturities, calls and principal repayments	218,136	148,979
Net change in loans	(133,759)	75,427
Net cash paid in acquisitions	(7,199)
Proceeds from sales of premises and equipment	214	988
Purchases of premises and equipment	(8,276)	(3,586)
Proceeds from sales of repossessed properties	4,522	3,599
Net cash from investing activities	(925,277)	(479,796)
Financing Activities:
Net change in deposits	152,273	230,217
Net change in short-term borrowings	(85,104)	77,898
Principal payments on long-term borrowings	(4)	(5)
Proceeds from stock option exercises	5,542	5,769
Excess tax benefits from stock-based compensation	41	154
Purchase of treasury stock		(201)
Cash dividends paid	(28,239)	(27,579)
Net cash from financing activities	44,509	286,253
Net change in cash and cash equivalents	(778,858)	(122,306)
Cash and equivalents at beginning of period	2,907,592	2,820,977
Cash and equivalents at end of period	$ 2,128,734	$ 2,698,671