Consolidated Statements Of Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Loans including fees:
Taxable	$ 257,176	$ 228,480	$ 175,607
Nontaxable	8,858	9,419	9,631
Investment securities, available-for-sale:
Taxable	44,059	51,682	71,057
Nontaxable	15,722	13,571	16,294
Investment securities, held-to-maturity, taxable	18,830	23,079	23,828
Money market and other interest-earning investments	54	362	431
Total interest income	344,699	326,593	296,848
Interest Expense
Deposits	27,042	35,911	48,608
Short-term borrowings	539	550	662
Other borrowings	8,361	17,259	29,162
Total interest expense	35,942	53,720	78,432
Net interest income	308,757	272,873	218,416
Provision for loan losses	5,030	7,473	30,781
Net interest income after provision for loan losses	303,727	265,400	187,635
Noninterest Income
Wealth management fees	21,549	20,460	16,120
Service charges on deposit accounts	51,483	51,862	50,018
ATM fees	24,006	25,199	22,967
Mortgage banking revenue	3,742	3,250	2,230
Insurance premiums and commissions	37,103	36,957	36,463
Investment product fees	12,714	11,068	9,192
Company-owned life insurance	6,452	5,322	4,052
Net securities gains	15,052	8,691	17,124
Total other-than-temporary impairment losses	(1,414)	(3,252)	(5,060)
Loss recognized in other comprehensive income	0	1,843	1,133
Impairment losses recognized in earnings	(1,414)	(1,409)	(3,927)
Gain on derivatives	820	974	1,492
Gain on sale leaseback transactions	6,423	7,864	6,452
Change in FDIC indemnification asset	(3,375)	426	0
Other income	15,261	12,219	7,967
Total noninterest income	189,816	182,883	170,150
Noninterest Expense
Salaries and employee benefits	193,874	189,539	170,601
Occupancy	50,929	51,054	46,410
Equipment	11,744	11,720	10,641
Marketing	7,451	5,990	5,720
Data processing	22,014	22,971	21,409
Communication	10,939	10,406	9,803
Professional fees	12,030	14,959	8,253
Loan expense	7,037	4,734	3,936
Supplies	2,719	3,762	2,935
Loss on extinguishment of debt	1,949	789	6,107
FDIC assessment	5,991	7,523	8,370
Other real estate owned expense	17,136	1,992	2,613
Amortization of intangibles	7,941	8,829	6,130
Other expense	14,004	14,253	11,377
Total noninterest expense	365,758	348,521	314,305
Income before income taxes	127,785	99,762	43,480
Income tax expense	36,110	27,302	5,266
Net income	$ 91,675	$ 72,460	$ 38,214
Net income per common share - basic	$ 0.95	$ 0.76	$ 0.44
Net income per common share - diluted	$ 0.95	$ 0.76	$ 0.44
Weighted average number of common shares outstanding-basic	96,440	94,467	86,785
Weighted average number of common shares outstanding-diluted	96,833	94,772	86,928
Dividends per common share	$ 0.36	$ 0.28	$ 0.28