Loans and Leases (Age Analysis of Past Due Financing Receivables) (Detail) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Financing Receivables That Are Accruing [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	$ 47,843	$ 57,241
60-89 Days Past Due	11,197	22,754
Greater than 90 Days	6,396	8,209
Total Past Due	65,436	88,204
Current	12,830,916	12,708,770
Total Financing Receivables,Accruing	12,896,352	12,796,974
Financing Receivables That Are Accruing [Member] | Originated Loans And Leases [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	42,585	51,679
60-89 Days Past Due	10,557	21,471
Greater than 90 Days	5,490	5,720
Total Past Due	58,632	78,870
Current	10,846,201	10,596,166
Total Financing Receivables,Accruing	10,904,833	10,675,036
Financing Receivables That Are Accruing [Member] | Purchased Loans And Leases [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	5,258	5,562
60-89 Days Past Due	640	1,283
Greater than 90 Days	906	2,489
Total Past Due	6,804	9,334
Current	1,984,715	2,112,604
Total Financing Receivables,Accruing	1,991,519	2,121,938
Financing Receivables That Are Accruing [Member] | Commercial Loan [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	4,106	5,163
60-89 Days Past Due	783	762
Greater than 90 Days	988	359
Total Past Due	5,877	6,284
Current	2,297,241	2,256,863
Total Financing Receivables,Accruing	2,303,118	2,263,147
Financing Receivables That Are Accruing [Member] | Real Estate - Construction [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	1,206	8,568
60-89 Days Past Due	575	1,614
Greater than 90 Days	382	157
Total Past Due	2,163	10,339
Current	758,236	822,625
Total Financing Receivables,Accruing	760,399	832,964
Financing Receivables That Are Accruing [Member] | Real Estate Secured - Residential [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	19,043	19,544
60-89 Days Past Due	3,863	4,467
Greater than 90 Days	4,237	5,547
Total Past Due	27,143	29,558
Current	4,020,295	4,007,820
Total Financing Receivables,Accruing	4,047,438	4,037,378
Financing Receivables That Are Accruing [Member] | Real Estate Secured - Commercial [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	9,687	9,623
60-89 Days Past Due	5,427	13,746
Greater than 90 Days	0	1,394
Total Past Due	15,114	24,763
Current	3,912,983	3,897,224
Total Financing Receivables,Accruing	3,928,097	3,921,987
Financing Receivables That Are Accruing [Member] | Consumer [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	10,336	8,898
60-89 Days Past Due	303	1,678
Greater than 90 Days	603	545
Total Past Due	11,242	11,121
Current	848,385	831,388
Total Financing Receivables,Accruing	859,627	842,509
Financing Receivables That Are Accruing [Member] | Leases [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	3,465	5,445
60-89 Days Past Due	246	487
Greater than 90 Days	186	207
Total Past Due	3,897	6,139
Current	993,776	892,850
Total Financing Receivables,Accruing	997,673	898,989
Financing Receivables That Are Nonaccruing [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	6,123	4,067
60-89 Days Past Due	5,175	2,784
Greater than 90 Days	68,265	70,507
Total Past Due	79,563	77,358
Current	23,788	20,409
Total Financing Receivables, Nonaccruing	103,351	97,767
Financing Receivables That Are Nonaccruing [Member] | Originated Loans And Leases [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	5,705	4,067
60-89 Days Past Due	4,453	2,379
Greater than 90 Days	63,155	65,830
Total Past Due	73,313	72,276
Current	20,153	18,146
Total Financing Receivables, Nonaccruing	93,466	90,422
Financing Receivables That Are Nonaccruing [Member] | Purchased Loans And Leases [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	418	0
60-89 Days Past Due	722	405
Greater than 90 Days	5,110	4,677
Total Past Due	6,250	5,082
Current	3,635	2,263
Total Financing Receivables, Nonaccruing	9,885	7,345
Financing Receivables That Are Nonaccruing [Member] | Commercial Loan [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	632	631
60-89 Days Past Due	725	649
Greater than 90 Days	4,876	6,068
Total Past Due	6,233	7,348
Current	3,309	3,116
Total Financing Receivables, Nonaccruing	9,542	10,464
Financing Receivables That Are Nonaccruing [Member] | Real Estate - Construction [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	1,983	405
Greater than 90 Days	15,798	14,047
Total Past Due	17,781	14,452
Current	1,164	365
Total Financing Receivables, Nonaccruing	18,945	14,817
Financing Receivables That Are Nonaccruing [Member] | Real Estate Secured - Residential [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	2,342	953
60-89 Days Past Due	330	452
Greater than 90 Days	19,204	19,551
Total Past Due	21,876	20,956
Current	8,496	7,484
Total Financing Receivables, Nonaccruing	30,372	28,440
Financing Receivables That Are Nonaccruing [Member] | Real Estate Secured - Commercial [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	3,149	2,483
60-89 Days Past Due	1,682	622
Greater than 90 Days	28,171	30,433
Total Past Due	33,002	33,538
Current	10,339	9,083
Total Financing Receivables, Nonaccruing	43,341	42,621
Financing Receivables That Are Nonaccruing [Member] | Consumer [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	0	0
Greater than 90 Days	0	0
Total Past Due	0	0
Current	37	43
Total Financing Receivables, Nonaccruing	37	43
Financing Receivables That Are Nonaccruing [Member] | Leases [Member]
Financing Receivable Recorded Investment Past Due [Line Items]
30-59 Days Past Due	0	0
60-89 Days Past Due	455	656
Greater than 90 Days	216	408
Total Past Due	671	1,064
Current	443	318
Total Financing Receivables, Nonaccruing	$ 1,114	$ 1,382