Loans (Summary Of Loan Portfolio) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 12,516,892	$ 11,828,943	$ 11,202,842
Covered loans	454,602	560,087	614,062
Total loans	12,971,494	12,389,030	11,816,904
Total loans, percentage	96.00%	96.00%	95.00%
Covered loans, percentage	4.00%	4.00%	5.00%
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	107,710	103,985	107,931
Total loans, percentage	1.00%	1.00%	1.00%
Indirect Consumer [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	64,521	77,333	72,482
Total loans, percentage	1.00%	1.00%	1.00%
Premium Finance Receivable [Member] | Commercial Insurance Loans [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	2,165,734	1,987,856	1,830,044
Total loans, percentage	16.00%	16.00%	15.00%
Premium Finance Receivable [Member] | Premium Finance Receivables Life Insurance [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	1,821,147	1,725,166	1,656,200
Total loans, percentage	14.00%	14.00%	14.00%
Residential Portfolio Segment [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	384,961	367,213	375,494
Total loans, percentage	3.00%	3.00%	3.00%
Home Equity Line of Credit [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	758,260	788,474	820,991
Total loans, percentage	6.00%	6.00%	7.00%
Commercial Real Estate Portfolio Segment [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	4,093,983	3,864,118	3,666,519
Total loans, percentage	31.00%	31.00%	31.00%
Commercial Portfolio Segment [Member]
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 3,120,576	$ 2,914,798	$ 2,673,181
Total loans, percentage	24.00%	24.00%	23.00%