Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Interest income:
Loans, including fees	$ 397,855	$ 409,651	$ 432,222
Securities:
Taxable	127,072	121,402	125,084
Tax-exempt	91,672	81,311	63,362
Interest-bearing deposits	6,357	4,901	2,161
Federal funds sold and resell agreements	61	74	207
Total interest income	623,017	617,339	623,036
Interest expense:
Deposits	22,179	29,973	56,015
Federal funds purchased and repurchase agreements	312	437	1,052
Junior subordinated deferrable interest debentures	6,783	6,982	7,231
Other long-term borrowings	11,967	16,488	22,059
Total interest expense	41,241	53,880	86,357
Net interest income	581,776	563,459	536,679
Provision for loan losses	27,445	43,611	65,392
Net interest income after provision for loan losses	554,331	519,848	471,287
Non-interest income:
Trust fees	73,233	68,428	67,268
Service charges on deposit accounts	94,367	98,796	102,474
Insurance commissions and fees	35,421	34,015	33,096
Other charges, commissions and fees	34,005	30,452	27,699
Net gain (loss) on securities transactions	6,414	6	(1,260)
Other	46,562	50,336	64,429
Total non-interest income	290,002	282,033	293,706
Non-interest expense:
Salaries and wages	252,028	239,589	230,643
Employee benefits	52,939	52,352	55,224
Net occupancy	46,968	46,166	44,188
Furniture and equipment	51,469	47,651	44,223
Deposit insurance	12,714	20,451	25,812
Intangible amortization	4,387	5,125	6,537
Other	137,593	124,207	125,611
Total non-interest expense	558,098	535,541	532,238
Income before income taxes	286,235	266,340	232,755
Income taxes	68,700	57,576	53,721
Net income	$ 217,535	$ 208,764	$ 179,034
Earnings per common share:
Basic	$ 3.55	$ 3.44	$ 3.00
Diluted	$ 3.54	$ 3.44	$ 3.00