CONSOLIDATED STATEMENTS OF INCOME (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Interest Income
Interest and fees on loans	$ 581,696	$ 547,365	$ 543,009
Interest and dividends on investment securities:
Taxable	68,698	108,129	115,593
Tax-exempt	13,157	11,273	10,366
Dividends	7,107	6,655	7,428
Interest on federal funds sold and other short-term investments	535	402	416
Total interest income	671,193	673,824	676,812
Interest Expense
Savings, NOW and money market	20,090	19,876	19,126
Time	37,466	48,291	55,798
Interest on short-term borrowings	1,387	1,154	1,345
Interest on long-term borrowings and junior subordinated debentures	122,369	129,692	137,791
Total interest expense	181,312	199,013	214,060
Net Interest Income	489,881	474,811	462,752
Provision for credit losses	25,552	53,335	49,456
Net Interest Income After Provision for Credit Losses	464,329	421,476	413,296
Non-Interest Income
Trust and investment services	7,690	7,523	7,665
Insurance commissions	15,494	15,627	11,334
Service charges on deposit accounts	24,752	22,610	25,691
Gains on securities transactions, net	2,587	32,068	11,598
Other-than-temporary impairment losses on securities		(42,775)	(1,393)
Portion recognized in other comprehensive income (loss)(before taxes)	(5,247)	22,807	(3,249)
Net impairment losses on securities recognized in earnings	(5,247)	(19,968)	(4,642)
Trading gains (losses), net	2,793	2,271	(6,897)
Fees from loan servicing	4,843	4,337	4,919
Gains on sales of loans, net	46,998	10,699	12,591
(Losses) gains on sales of assets, net	(329)	426	619
Bank owned life insurance	6,855	7,380	6,166
Change in FDIC loss-share receivable	(7,459)	13,403	6,268
Other	21,969	15,921	16,015
Total non-interest income	120,946	112,297	91,327
Non-Interest Expense
Salary and employee benefits expense	199,968	176,307	176,106
Net occupancy and equipment expense	71,245	66,332	63,771
FDIC insurance assessment	14,292	12,759	13,719
Amortization of other intangible assets	9,783	9,315	7,721
Professional and legal fees	15,005	15,312	10,137
Advertising	7,103	8,373	4,052
Other	57,504	50,158	44,182
Total non-interest expense	374,900	338,556	319,688
Income (loss) before income taxes	210,375	195,217	184,935
Income tax expense	66,748	62,706	54,929
Net Income	$ 143,627	$ 132,511	$ 130,006
Earnings Per Common Share:
Basic	$ 0.73	$ 0.74	$ 0.73
Diluted	$ 0.73	$ 0.74	$ 0.73
Cash dividends declared per common share	$ 0.65	$ 0.66	$ 0.66
Weighted Average Number of Common Shares Outstanding:
Basic	197,354,159	178,424,883	177,568,546
Diluted	197,354,372	178,426,070	177,577,663