Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Interest income:
Loans, including fees	$ 98,336	$ 99,811	$ 195,687	$ 198,299
Securities:
Taxable	34,399	31,668	70,465	62,853
Tax-exempt	22,125	23,169	44,628	45,902
Interest-bearing deposits	903	1,472	1,833	2,643
Federal funds sold and resell agreements	33	13	48	29
Total interest income	155,796	156,133	312,661	309,726
Interest expense:
Deposits	4,547	5,946	9,119	11,897
Federal funds purchased and repurchase agreements	34	83	68	214
Junior subordinated deferrable interest debentures	1,711	1,691	3,385	3,363
Other long-term borrowings	287	4,080	1,165	8,160
Total interest expense	6,579	11,800	13,737	23,634
Net interest income	149,217	144,333	298,924	286,092
Provision for loan losses	2,355	8,985	3,455	18,435
Net interest income after provision for loan losses	146,862	135,348	295,469	267,657
Non-interest income:
Trust and investment management fees	21,279	20,313	41,931	39,784
Service charges on deposit accounts	20,639	21,328	41,433	42,578
Insurance commissions and fees	9,171	7,908	21,548	18,402
Interchange and debit card transaction fees	4,292	8,695	8,409	16,740
Other charges, commissions and fees	7,825	6,825	15,175	14,053
Net gain (loss) on securities transactions	370		(121)	5
Other	6,187	5,723	13,367	11,563
Total non-interest income	69,763	70,792	141,742	143,125
Non-interest expense:
Salaries and wages	62,624	61,775	126,326	124,205
Employee benefits	14,048	13,050	30,749	28,361
Net occupancy	12,213	11,823	24,010	23,475
Furniture and equipment	13,734	12,628	27,154	24,909
Deposit insurance	2,838	2,598	5,335	7,358
Intangible amortization	994	1,107	2,005	2,227
Other	36,085	33,816	68,997	66,323
Total non-interest expense	142,536	136,797	284,576	276,858
Income before income taxes	74,089	69,343	152,635	133,924
Income taxes	16,027	13,657	33,540	26,310
Net income	$ 58,062	$ 55,686	$ 119,095	$ 107,614
Earnings per common share:
Basic	$ 0.94	$ 0.91	$ 1.94	$ 1.76
Diluted	$ 0.94	$ 0.91	$ 1.93	$ 1.75