Loans (Summary Of Loan Portfolio) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 11,900,312	$ 11,828,943	$ 10,717,384
Covered loans	518,661	560,087	691,220
Total loans	12,418,973	12,389,030	11,408,604
Total loans, percentage	96.00%	96.00%	94.00%
Covered loans, percentage	4.00%	4.00%	6.00%
Percentage of Loans Net of Unearned Income Including Covered Loans	100.00%	100.00%	100.00%
Consumer And Other [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	97,365	103,985	111,639
Total loans, percentage	1.00%	1.00%	1.00%
Indirect Consumer [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	69,245	77,333	67,445
Total loans, percentage	1.00%	1.00%	1.00%
Residential Real-Estate [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	360,652	367,213	361,327
Total loans, percentage	3.00%	3.00%	3.00%
Commercial Real Estate Portfolio Segment [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	3,990,465	3,864,118	3,585,760
Total loans, percentage	32.00%	31.00%	32.00%
Commercial Portfolio Segment [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	2,872,695	2,914,798	2,544,456
Total loans, percentage	23.00%	24.00%	22.00%
Home Equity [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	759,218	788,474	840,364
Total loans, percentage	6.00%	6.00%	7.00%
Commercial Insurance Loans [Member] | Premium Finance Receivable [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	1,997,160	1,987,856	1,512,630
Total loans, percentage	16.00%	16.00%	13.00%
Premium Finance Receivables Life Insurance [Member] | Premium Finance Receivable [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 1,753,512	$ 1,725,166	$ 1,693,763
Total loans, percentage	14.00%	14.00%	15.00%