Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Operating Activities
Net Income	$ 110,410	$ 87,047	$ 74,652
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation, amortization and accretion	31,827	22,427	27,259
Provision for loan losses	31,302	33,641	47,323
Deferred income taxes	29,251	7,063	(50)
Gain on sale of securities	(305)	(3,652)	(2,960)
Other-than-temporary impairment losses on securities	212	66	2,339
Tax expense of stock-based compensation	(386)	61	199
Net change in:
Interest receivable	(1,569)	1,416	1,874
Interest payable	(3,925)	(1,602)	(2,085)
Residential mortgage loans held for sale	(13,477)	(1,574)	54
Trading securities	331,972	110,490
Bank owned life insurance	(6,130)	(842)	(2,929)
Other, net	34,848	34,989	17,147
Net cash flows provided by operating activities	544,030	289,530	162,823
Investing Activities
Net increase in loans	(409,590)	(412,462)	(312,564)
Securities available for sale:
Purchases	(924,747)	(429,831)	(433,809)
Sales	87,101	101,973	60,165
Maturities	450,064	431,219	353,115
Securities held to maturity:
Purchases	(526,252)	(243,461)	(434,393)
Sales	2,903		7,644
Maturities	340,401	262,307	258,718
Purchase of bank owned life insurance	(25,032)	(34)	(35)
Withdrawal/surrender of bank owned life insurance	20,891		360
Increase in premises and equipment	(12,780)	(17,115)	(9,810)
Net cash received for mergers and acquisitions	203,538	23,374
Net cash flows used in investing activities	(793,503)	(284,030)	(510,609)
Financing Activities
Non-interest bearing deposits, savings, and NOW accounts	614,100	298,833	341,867
Time deposits	(337,822)	(196,520)	(75,946)
Short-term borrowings	218,904	72,580	84,436
Increase in long-term debt	40,315	52,827	125,884
Decrease in long-term debt	(197,568)	(166,144)	(258,703)
Net proceeds from issuance of common stock	8,895	71,053	6,723
Tax expense of stock-based compensation	386	(61)	(199)
Cash dividends paid	(67,646)	(60,686)	(55,255)
Net cash flows (used in) provided by financing activities	279,564	71,882	168,807
Net Increase (Decrease) in Cash and Cash Equivalents	30,091	77,382	(178,979)
Cash and cash equivalents at beginning of year	208,953	131,571	310,550
Cash and Cash Equivalents at End of Year	$ 239,044	$ 208,953	$ 131,571