Allowance For Loan Losses, Allowance For Losses On Lending-Related Commitments And Impaired Loans (Summary Of Recorded Investment Based On Performance Of Loans By Class) (Detail) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011		Sep. 30, 2011
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 11,489,900		$ 10,521,377		$ 10,272,711
Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,771,053		2,498,313		2,337,098
Commercial Portfolio Segment [Member] | Commercial And Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,556,375		1,450,451		1,414,715
Commercial Portfolio Segment [Member] | Franchise [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	179,706		142,775		126,854
Commercial Portfolio Segment [Member] | Warehouse Agreement Borrowings [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	225,295		180,450		132,425
Commercial Portfolio Segment [Member] | Community Advantage - Homeowners Association [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	73,881		77,504		74,281
Commercial Portfolio Segment [Member] | Aircraft [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	21,444		20,397		18,080
Commercial Portfolio Segment [Member] | Asset-Based Lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	533,061		465,737		419,737
Commercial Portfolio Segment [Member] | Municipal Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	90,404		78,319		74,723
Commercial Portfolio Segment [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	83,351		72,134		66,671
Commercial Portfolio Segment [Member] | Other Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,576		2,125		2,044
Commercial Portfolio Segment [Member] | Purchased Non-Covered Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	5,960	[1],[2]	8,421	[1],[2]	7,568	[1],[2]
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,699,712		3,514,261		3,465,321
Commercial Real Estate Portfolio Segment [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	44,255		65,811		71,941
Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	169,543		169,876		160,421
Commercial Real Estate Portfolio Segment [Member] | Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	133,486		178,531		199,130
Commercial Real Estate Portfolio Segment [Member] | Office [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	584,321		554,446		533,930
Commercial Real Estate Portfolio Segment [Member] | Industrial Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	574,325		555,802		538,248
Commercial Real Estate Portfolio Segment [Member] | Retail Site [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	560,669		536,729		519,235
Commercial Real Estate Portfolio Segment [Member] | Multi Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	363,423		314,557		324,777
Commercial Real Estate Portfolio Segment [Member] | Mixed Use And Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,220,850		1,086,654		1,063,282
Commercial Real Estate Portfolio Segment [Member] | Purchased Non-Covered Commercial Real-Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	48,840	[1],[2]	51,855	[1],[2]	54,357	[1],[2]
Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	807,592		862,345		879,180
Residential Real-Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	376,022		349,596		326,207
Residential Real-Estate [Member] | Purchased Non Covered Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	656	[1],[2]	693	[1],[2]	0	[1],[2]
Premium Finance Receivable [Member] | Commercial Insurance Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,982,945		1,412,454		1,417,572
Premium Finance Receivable [Member] | Life Insurance Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,128,588		1,096,762		1,035,667
Premium Finance Receivable [Member] | Purchased Life Insurance Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	537,032	[1],[2]	598,463	[1],[2]	635,776	[1],[2]
Indirect Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	77,378		64,545		62,452
Consumer And Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	108,855		123,866		112,801
Consumer And Other [Member] | Purchased Non Covered Consumer And Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	67	[1],[2]	79	[1],[2]	637	[1],[2]
Performing Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	11,372,009		10,401,293		10,138,735
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,753,342		2,479,295		2,312,262
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,541,212		1,434,297		1,393,660
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Franchise [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	177,914		140,983		125,062
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Warehouse Agreement Borrowings [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	225,295		180,450		132,425
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Community Advantage - Homeowners Association [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	73,881		77,504		74,281
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Aircraft [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	21,016		20,397		18,080
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Asset-Based Lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	532,733		464,665		417,748
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Municipal Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	90,404		78,319		74,723
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	83,351		72,134		66,671
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Other Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,576		2,125		2,044
Performing Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Purchased Non-Covered Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	5,960	[1]	8,421	[1]	7,568	[1]
Performing Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,641,251		3,447,753		3,394,547
Performing Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	42,114		63,818		69,478
Performing Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	166,228		167,718		157,561
Performing Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	122,857		146,984		168,058
Performing Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Office [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	578,136		543,832		518,498
Performing Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Industrial Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	572,440		553,800		536,088
Performing Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Retail Site [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	550,536		531,363		515,571
Performing Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Multi Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	360,109		309,821		321,354
Performing Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Mixed Use And Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,199,991		1,078,562		1,053,582
Performing Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Purchased Non-Covered Commercial Real-Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	48,840	[1]	51,855	[1]	54,357	[1]
Performing Financing Receivable [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	796,088		848,181		863,754
Performing Financing Receivable [Member] | Residential Real-Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	360,629		342,977		318,661
Performing Financing Receivable [Member] | Residential Real-Estate [Member] | Purchased Non Covered Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	656	[1]	693	[1]	0	[1]
Performing Financing Receivable [Member] | Premium Finance Receivable [Member] | Commercial Insurance Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,969,924		1,399,418		1,406,031
Performing Financing Receivable [Member] | Premium Finance Receivable [Member] | Life Insurance Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,128,559		1,096,708		1,032,905
Performing Financing Receivable [Member] | Premium Finance Receivable [Member] | Purchased Life Insurance Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	537,032	[1]	598,463	[1]	635,776	[1]
Performing Financing Receivable [Member] | Indirect Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	77,091		64,093		62,014
Performing Financing Receivable [Member] | Consumer And Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	107,370		123,633		112,148
Performing Financing Receivable [Member] | Consumer And Other [Member] | Purchased Non Covered Consumer And Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	67	[1]	79	[1]	637	[1]
Nonperforming Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	117,891		120,084		133,976
Nonperforming Financing Receivable [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	17,711		19,018		24,836
Nonperforming Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	15,163		16,154		21,055
Nonperforming Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Franchise [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,792		1,792		1,792
Nonperforming Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Warehouse Agreement Borrowings [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0		0		0
Nonperforming Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Community Advantage - Homeowners Association [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0		0		0
Nonperforming Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Aircraft [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	428		0		0
Nonperforming Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Asset-Based Lending [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	328		1,072		1,989
Nonperforming Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Municipal Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0		0		0
Nonperforming Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Leases [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0		0		0
Nonperforming Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Other Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0		0		0
Nonperforming Financing Receivable [Member] | Commercial Portfolio Segment [Member] | Purchased Non-Covered Commercial [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0	[1]	0	[1]	0	[1]
Nonperforming Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	58,461		66,508		70,774
Nonperforming Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,141		1,993		2,463
Nonperforming Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Commercial Real Estate Construction Financing Receivable [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,315		2,158		2,860
Nonperforming Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	10,629		31,547		31,072
Nonperforming Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Office [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	6,185		10,614		15,432
Nonperforming Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Industrial Property [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,885		2,002		2,160
Nonperforming Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Retail Site [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	10,133		5,366		3,664
Nonperforming Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Multi Family [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,314		4,736		3,423
Nonperforming Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Mixed Use And Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	20,859		8,092		9,700
Nonperforming Financing Receivable [Member] | Commercial Real Estate Portfolio Segment [Member] | Purchased Non-Covered Commercial Real-Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0	[1]	0	[1]	0	[1]
Nonperforming Financing Receivable [Member] | Home Equity [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	11,504		14,164		15,426
Nonperforming Financing Receivable [Member] | Residential Real-Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	15,393		6,619		7,546
Nonperforming Financing Receivable [Member] | Residential Real-Estate [Member] | Purchased Non Covered Residential Real Estate [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0	[1]	0	[1]	0	[1]
Nonperforming Financing Receivable [Member] | Premium Finance Receivable [Member] | Commercial Insurance Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	13,021		13,036		11,541
Nonperforming Financing Receivable [Member] | Premium Finance Receivable [Member] | Life Insurance Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	29		54		2,762
Nonperforming Financing Receivable [Member] | Premium Finance Receivable [Member] | Purchased Life Insurance Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0	[1]	0	[1]	0	[1]
Nonperforming Financing Receivable [Member] | Indirect Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	287		452		438
Nonperforming Financing Receivable [Member] | Consumer And Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,485		233		653
Nonperforming Financing Receivable [Member] | Consumer And Other [Member] | Purchased Non Covered Consumer And Other [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 0	[1]	$ 0	[1]	$ 0	[1]

[1] Purchased loans represent loans acquired with evidence of credit quality deterioration since origination, in accordance with ASC 310-30.

[2] Purchased loans represent loans acquired with evidence of credit quality deterioration since origination, in accordance with ASC 310-30. Loan agings are based upon contractually required payments.