Consolidated Statements of Income and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Interest income:
Loans and loans held for sale	$ 410,299	$ 438,393	$ 433,763
Investment securities:
Taxable	85,030	87,044	95,527
Tax-exempt	15,354	12,819	13,080
Total investment securities interest	100,384	99,863	108,607
Total interest income	510,683	538,256	542,370
Interest expense:
Demand-interest bearing	987	816	751
Savings and money market accounts	20,563	28,171	31,912
Certificates and other time deposits	11,723	20,003	32,713
Securities sold under agreements to repurchase	1,157	3,344	4,477
Wholesale borrowings	4,423	6,295	13,998
Total interest expense	38,853	58,629	83,851
Net interest income	471,830	479,627	458,519
Provision for noncovered loan losses	33,976	54,035	83,783
Provision for covered loan losses	20,722	20,353	4,432
Net interest income after provision for loan losses	417,132	405,239	370,304
Other income:
Trust department income	23,143	22,396	21,951
Service charges on deposits	57,737	64,082	65,900
Credit card fees	43,569	49,539	49,010
ATM and other service fees	14,792	13,701	11,259
Bank owned life insurance income	12,140	14,820	14,949
Investment services and insurance	8,990	8,228	9,451
Investment securities gains, net	3,786	11,081	855
Loan sales and servicing income	27,031	14,205	21,649
Gain on George Washington acquisition	0	0	1,041
Other operating income	32,416	26,705	16,491
Total other income	223,604	224,757	212,556
Other expenses:
Salaries, wages, pension and employee benefits	245,192	240,362	221,316
Net occupancy expense	31,754	32,414	32,665
Equipment expense	29,243	27,959	27,664
Stationery, supplies and postage	8,800	10,691	11,438
Bankcard, loan processing and other costs	34,195	32,226	31,572
Professional services	23,480	23,229	29,357
Amortization of intangibles	1,866	2,172	2,914
FDIC expense	10,753	17,306	17,790
Other operating expense	68,330	77,986	68,144
Total other expenses	453,613	464,345	442,860
Income before income tax expense	187,123	165,651	140,000
Income tax expense	53,017	46,093	37,091
Net income	134,106	119,558	102,909
Other comprehensive income (loss), net of taxes:
Changes in unrealized securities' holding gains and losses, net of taxes of $2.2 million, $10.2 million and $0.0 million	4,154	26,205	(555)
Reclassification for realized securities' gains, net of taxes of $1.3 million, $3.9 million and $0.3 million	(2,461)	(7,203)	(556)
Pension and postretirement benefit costs, net of taxes of $3.2 million, $9.0 million and $0.3 million	5,989	(16,786)	467
Total other comprehensive gain (loss), net of taxes	7,682	2,216	(644)
Comprehensive income	141,788	121,774	102,265
Net income available to common shareholders	134,106	119,558	102,909
Net income used in diluted EPS calculation	$ 134,106	$ 119,558	$ 102,909
Weighted average number of common shares outstanding - basic	109,518	109,102	101,163
Average common shares outstanding	109,518	109,102	101,165
Basic earnings per common share (in dollars per share)	$ 1.22	$ 1.10	$ 1.02
Diluted earnings per common share (in dollars per share)	$ 1.22	$ 1.10	$ 1.02
Dividend per common share (in dollars per share)	$ 0.64	$ 0.64	$ 0.64