Loans (Summary Of Loan Portfolio) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 13,133,160	$ 12,896,602	$ 11,900,312
Covered loans	312,478	346,431	518,661
Total loans	13,445,638	13,243,033	12,418,973
Total loans, percentage	98.00%	97.00%	96.00%
Covered loans, percentage	2.00%	3.00%	4.00%
Percentage of Loans Net of Unearned Income Including Covered Loans	100.00%	100.00%	100.00%
Commercial
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	3,439,197	3,253,687	2,872,695
Total loans, percentage	26.00%	25.00%	23.00%
Commercial real-estate
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	4,262,255	4,230,035	3,990,465
Total loans, percentage	32.00%	32.00%	32.00%
Home equity
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	707,748	719,137	759,218
Total loans, percentage	5.00%	5.00%	6.00%
Residential real-estate
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	426,769	434,992	360,652
Total loans, percentage	3.00%	3.00%	3.00%
Premium finance receivables | Commercial insurance loans
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	2,208,361	2,167,565	1,997,160
Total loans, percentage	17.00%	16.00%	16.00%
Premium finance receivables | Life insurance
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	1,929,334	1,923,698	1,753,512
Total loans, percentage	14.00%	15.00%	14.00%
Consumer and other
Loans [Line Items]
Loans, net of unearned income, excluding covered loans	$ 159,496	$ 167,488	$ 166,610
Total loans, percentage	1.00%	1.00%	2.00%