Consolidated Statement of Income (Loss) (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
INTEREST INCOME
Interest and fees on loans	$ 598,582	$ 587,526	$ 595,965
Interest and dividends on investment securities
Taxable	102,464	88,919	86,945
Tax exempt	29,064	27,345	28,655
Other interest	6,635	5,193	6,719
Total interest income	736,745	708,983	718,284
INTEREST EXPENSE
Interest on deposits	26,294	31,267	41,431
Interest on Federal funds purchased and securities sold under agreements to repurchase	1,219	1,322	2,687
Interest on other short-term funding	785	1,519	3,294
Interest on long-term funding	27,480	29,332	44,880
Total interest expense	55,778	63,440	92,292
NET INTEREST INCOME	680,967	645,543	625,992
Provision for credit losses	16,000	10,100	10,100
Net interest income after provision for credit losses	664,967	635,443	615,892
NONINTEREST INCOME
Trust service fees	48,403	45,633	40,737
Service charges on deposit accounts	68,779	70,009	68,917
Card-based and other nondeposit fees	49,512	49,913	47,862
Insurance commissions	44,421	44,024	47,014
Brokerage and annuity commissions	16,089	14,877	15,643
Mortgage banking, net	21,320	48,847	63,500
Capital market fees, net	9,973	13,080	14,241
Bank owned life insurance income	13,576	11,855	13,952
Asset gains (losses), net	10,288	5,413	(12,096)
Investment securities gains (losses), net:
Realized gains (losses), net	494	564	4,261
Other-than-temporary impairments	0	0	(59)
Less: Non-credit portion recognized in other comprehensive income (before taxes)	0	0	59
Investment securities gains (losses), net	494	564	4,261
Other	7,464	8,884	9,259
Total noninterest income	290,319	313,099	313,290
NONINTEREST EXPENSE
Personnel expense	390,399	397,015	381,404
Occupancy	57,677	59,409	60,794
Equipment	24,784	25,351	23,566
Technology	55,472	49,445	43,548
Business development and advertising	26,144	23,346	21,303
Other intangible amortization	3,747	4,043	4,195
Loan expense	13,866	13,162	12,285
Legal and professional fees	17,485	20,226	31,232
Foreclosure/OREO expense	6,722	10,068	15,069
FDIC expense	23,761	19,461	19,478
Other	59,184	59,123	61,849
Total noninterest expense	679,241	680,649	674,723
Income before income taxes	276,045	267,893	254,459
Income tax expense	85,536	79,201	75,486
Net income	190,509	188,692	178,973
Preferred stock dividends	5,002	5,158	5,200
Net income available to common equity	$ 185,507	$ 183,534	$ 173,773
Earnings per common share:
Basic	$ 1.17	$ 1.10	$ 1.00
Diluted	$ 1.16	$ 1.10	$ 1.00
Average common shares outstanding:
Basic	157,286	165,584	172,255
Diluted	158,254	165,802	172,357