Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Interest income:
Loans, including fees	$ 101,643	$ 99,737	$ 297,330	$ 298,036
Securities:
Taxable	32,091	30,089	102,556	92,942
Tax-exempt	23,283	23,127	67,911	69,029
Interest-bearing deposits	1,115	1,811	2,948	4,454
Federal funds sold and resell agreements	27	15	75	44
Total interest income	158,159	154,779	470,820	464,505
Interest expense:
Deposits	4,598	5,306	13,717	17,203
Federal funds purchased and repurchase agreements	37	63	105	277
Junior subordinated deferrable interest debentures	1,711	1,710	5,096	5,073
Other long-term borrowings	281	2,339	1,446	10,499
Total interest expense	6,627	9,418	20,364	33,052
Net interest income	151,532	145,361	450,456	431,453
Provision for loan losses	2,500	9,010	5,955	27,445
Net interest income after provision for loan losses	149,032	136,351	444,501	404,008
Non-interest income:
Trust and investment management fees	20,843	19,652	62,774	59,436
Service charges on deposit accounts	20,797	22,072	62,230	64,650
Insurance commissions and fees	9,964	9,569	31,512	27,971
Interchange and debit card transaction fees	4,194	8,719	12,603	25,459
Other charges, commissions and fees	7,265	6,572	22,440	20,625
Net gain (loss) on securities transactions		6,409	(121)	6,414
Other	8,095	6,224	21,462	17,787
Total non-interest income	71,158	79,217	212,900	222,342
Non-interest expense:
Salaries and wages	64,984	61,697	191,310	185,902
Employee benefits	14,019	12,004	44,768	40,365
Net occupancy	13,193	12,080	37,203	35,555
Furniture and equipment	14,193	13,106	41,347	38,015
Deposit insurance	2,593	2,583	7,928	9,941
Intangible amortization	973	1,108	2,978	3,335
Other	34,495	34,829	103,492	101,152
Total non-interest expense	144,450	137,407	429,026	414,265
Income before income taxes	75,740	78,161	228,375	212,085
Income taxes	17,071	23,654	50,611	49,964
Net income	$ 58,669	$ 54,507	$ 177,764	$ 162,121
Earnings per common share:
Basic	$ 0.95	$ 0.89	$ 2.89	$ 2.64
Diluted	$ 0.95	$ 0.89	$ 2.88	$ 2.64