Loans And Allowance For Loan Losses (Summary Of Commercial Loans By Credit Quality) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	$ 4,328,347	$ 3,970,214
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	2,597,029	2,341,646
Commercial Real Estate - FL [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	71,887	154,081
Commercial And Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	1,532,366	1,363,692
Commercial Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	127,065	110,795
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	4,018,953	3,578,997
Pass [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	2,397,479	2,127,334
Pass [Member] | Commercial Real Estate - FL [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	41,826	70,802
Pass [Member] | Commercial And Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	1,456,976	1,275,230
Pass [Member] | Commercial Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	122,672	105,631
Special Mention [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	91,309	142,347
Special Mention [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	62,324	73,701
Special Mention [Member] | Commercial Real Estate - FL [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	12,078	16,002
Special Mention [Member] | Commercial And Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	16,579	49,282
Special Mention [Member] | Commercial Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	328	3,362
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	212,365	246,828
Substandard [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	134,300	139,578
Substandard [Member] | Commercial Real Estate - FL [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	15,593	67,277
Substandard [Member] | Commercial And Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	58,407	38,171
Substandard [Member] | Commercial Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	4,065	1,802
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	5,720	2,042
Doubtful [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	2,926	1,033
Doubtful [Member] | Commercial Real Estate - FL [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	2,390
Doubtful [Member] | Commercial And Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Commercial and industrial	$ 404	$ 1,009