Loans And Allowance For Loan Losses (Age Analysis Of Past Due Loans, By Class) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013		Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 8,209,286		$ 8,137,719
Direct installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,192,426		1,178,530
Residential mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,072,898		1,092,228
Indirect installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	574,121		582,037
Consumer lines of credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	817,412		805,494
Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	31,608		39,937
Originated loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	34,909		46,205
> 90 Days Past Due and Still Accruing	5,974		6,707
Non- Accrual	65,578		66,004
Total Past Due	106,461		118,916
Current	7,260,031		7,118,475
Total Loans	7,366,492		7,237,391
Originated loans [Member] | Commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	7,320		5,786
> 90 Days Past Due and Still Accruing	523		533
Non- Accrual	46,274		47,895
Total Past Due	54,117		54,214
Current	2,375,160		2,394,257
Total Loans	2,429,277		2,448,471
Originated loans [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	2,177		7,310
> 90 Days Past Due and Still Accruing	456		456
Non- Accrual	10,110		6,017
Total Past Due	12,743		13,783
Current	1,655,317		1,541,518
Total Loans	1,668,060		1,555,301
Originated loans [Member] | Commercial leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	1,427		1,671
> 90 Days Past Due and Still Accruing
Non- Accrual	657		965
Total Past Due	2,084		2,636
Current	129,416		127,497
Total Loans	131,500		130,133
Originated loans [Member] | Commercial loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	10,924		14,767
> 90 Days Past Due and Still Accruing	979		989
Non- Accrual	57,041		54,877
Total Past Due	68,944		70,633
Current	4,159,893		4,063,272
Total Loans	4,228,837		4,133,905
Originated loans [Member] | Direct installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	7,555		8,834
> 90 Days Past Due and Still Accruing	2,602		2,717
Non- Accrual	3,875		3,342
Total Past Due	14,032		14,893
Current	1,116,064		1,093,972
Total Loans	1,130,096		1,108,865
Originated loans [Member] | Residential mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	10,389		15,821
> 90 Days Past Due and Still Accruing	1,769		2,365
Non- Accrual	3,424		2,891
Total Past Due	15,582		21,077
Current	648,199		632,749
Total Loans	663,781		653,826
Originated loans [Member] | Indirect installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	4,045		5,114
> 90 Days Past Due and Still Accruing	380		374
Non- Accrual	977		1,039
Total Past Due	5,402		6,527
Current	557,422		561,797
Total Loans	562,824		568,324
Originated loans [Member] | Consumer lines of credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	1,985		1,633
> 90 Days Past Due and Still Accruing	218		247
Non- Accrual	261		355
Total Past Due	2,464		2,235
Current	746,882		730,299
Total Loans	749,346		732,534
Originated loans [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	11		36
> 90 Days Past Due and Still Accruing	26		15
Non- Accrual			3,500
Total Past Due	37		3,551
Current	31,571		36,386
Total Loans	31,608		39,937
Acquired loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	13,872		22,799
> 90 Days Past Due and Still Accruing	41,234		36,585
Non- Accrual
Total Past Due	55,106	[1]	59,384	[1]
Current	832,207		890,478
Discount	(44,519)		(49,534)
Total Loans	842,794		900,328
Acquired loans [Member] | Commercial real estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	3,411		6,829
> 90 Days Past Due and Still Accruing	14,095		13,597
Non- Accrual
Total Past Due	17,506	[1]	20,426	[1]
Current	239,383		250,116
Discount	(7,643)		(11,967)
Total Loans	249,246		258,575
Acquired loans [Member] | Commercial and industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	929		1,653
> 90 Days Past Due and Still Accruing	4,086		138
Non- Accrual
Total Past Due	5,015	[1]	1,791	[1]
Current	39,723		47,351
Discount	(2,000)		(2,129)
Total Loans	42,738		47,013
Acquired loans [Member] | Commercial leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due
> 90 Days Past Due and Still Accruing
Non- Accrual
Total Past Due		[1]		[1]
Current
Discount
Total Loans
Acquired loans [Member] | Commercial loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	4,340		8,482
> 90 Days Past Due and Still Accruing	18,181		13,735
Non- Accrual
Total Past Due	22,521	[1]	22,217	[1]
Current	279,106		297,467
Discount	(9,643)		(14,096)
Total Loans	291,984		305,588
Acquired loans [Member] | Direct installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	865		1,454
> 90 Days Past Due and Still Accruing	1,324		947
Non- Accrual
Total Past Due	2,189	[1]	2,401	[1]
Current	56,579		63,502
Discount	3,562		3,762
Total Loans	62,330		69,665
Acquired loans [Member] | Residential mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	8,091		12,137
> 90 Days Past Due and Still Accruing	20,929		21,069
Non- Accrual
Total Past Due	29,020	[1]	33,206	[1]
Current	414,084		439,620
Discount	(33,987)		(34,424)
Total Loans	409,117		438,402
Acquired loans [Member] | Indirect installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	219		347
> 90 Days Past Due and Still Accruing	57		56
Non- Accrual
Total Past Due	276	[1]	403	[1]
Current	11,779		14,089
Discount	(758)		(779)
Total Loans	11,297		13,713
Acquired loans [Member] | Consumer lines of credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	357		379
> 90 Days Past Due and Still Accruing	743		778
Non- Accrual
Total Past Due	1,100	[1]	1,157	[1]
Current	70,659		75,800
Discount	(3,693)		(3,997)
Total Loans	68,066		72,960
Acquired loans [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due
> 90 Days Past Due and Still Accruing
Non- Accrual
Total Past Due		[1]		[1]
Current
Discount
Total Loans

[1] Past due information for loans acquired is based on the contractual balance outstanding at March 31, 2013 and December 31, 2012.