Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Summary of Impaired Loans by Loan Class) (Detail) - USD ($) $ in Thousands		6 Months Ended		12 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment	[1]	$ 50,748	$ 91,511	$ 69,487
Impaired Financing Receivable, Related Allowance		10,075	10,298	6,270
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		52,609	45,734	57,925
Impaired Financing Receivable, Recorded Investment	[2]	103,357	137,245	127,412
Impaired Financing Receivable, Unpaid Principal Balance		122,378	164,281	153,742
Impaired Financing Receivable, Average Recorded Investment		105,874	142,960	134,967
Impaired Financing Receivable, Interest Income Recognized		2,835	3,790	7,190
Commercial | Commercial and industrial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		6,702	7,220	9,989
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		7,141	10,152	10,785
Impaired Financing Receivable, Related Allowance		2,000	1,631	1,915
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		6,876	8,332	10,784
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		166	339	539
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		3,760	4,222	5,797
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		6,731	8,666	8,862
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		4,052	4,591	6,664
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		219	219	595
Commercial | Franchise
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		905	0	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		905	0	0
Impaired Financing Receivable, Related Allowance		200	0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		912	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		15	0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		0	0	0
Commercial | Mortgage warehouse lines of credit
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, Related Allowance		0	0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		0	0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		0	0	0
Commercial | Community Advanatage - homeowners association
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, Related Allowance		0	0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		0	0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		0	0	0
Commercial | Aircraft
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, Related Allowance		0	0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		0	0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		0	0	0
Commercial | Asset-based lending
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	270	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		0	290	0
Impaired Financing Receivable, Related Allowance		0	270	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0	275	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		0	7	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	25	25
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0	1,952	1,952
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	150	87
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		0	50	100
Commercial | Tax exempt
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, Related Allowance		0	0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		0	0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		0	0	0
Commercial | Leases
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		65	0	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		65	0	0
Impaired Financing Receivable, Related Allowance		65	0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		66	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		2	0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		0	0	0
Commercial | Other
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, Related Allowance		0	0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		0	0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		0	0	0
Commercial real estate | Residential construction
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, Related Allowance		0	0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		0	0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		2,023	0	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		2,023	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		2,023	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		48	0	0
Commercial real estate | Commercial construction
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	2,146	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		0	2,156	0
Impaired Financing Receivable, Related Allowance		0	128	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0	2,150	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		0	44	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		642	1,031	2,875
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		642	1,031	3,085
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		627	1,051	3,183
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		13	23	151
Commercial real estate | Land
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		6,924	11,687	5,011
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		10,539	15,538	8,626
Impaired Financing Receivable, Related Allowance		50	363	43
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		6,931	11,876	5,933
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		294	378	544
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		1,906	3,917	10,210
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		2,643	4,958	10,941
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		1,924	5,657	10,268
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		50	131	430
Commercial real estate | Office
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		7,005	14,403	11,038
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		7,010	15,159	12,863
Impaired Financing Receivable, Related Allowance		2,414	2,664	305
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		7,060	14,517	11,567
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		154	335	576
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		6,289	2,598	4,132
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		8,780	2,599	5,020
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		6,834	2,605	4,445
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		221	73	216
Commercial real estate | Industrial
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		1,218	3,349	195
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		1,218	3,455	277
Impaired Financing Receivable, Related Allowance		558	227	15
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		1,218	3,372	214
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		34	76	13
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		2,022	3,603	4,160
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		2,200	3,839	4,498
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		2,059	3,155	3,807
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		88	95	286
Commercial real estate | Retail
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		8,336	14,320	11,045
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		9,222	14,733	14,566
Impaired Financing Receivable, Related Allowance		404	1,590	487
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		8,482	14,343	12,116
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		194	304	606
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		4,099	6,422	5,487
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		5,248	7,813	7,470
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		4,113	6,456	6,915
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		112	188	330
Commercial real estate | Multi-family
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		2,149	2,835	2,808
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		2,258	3,349	3,321
Impaired Financing Receivable, Related Allowance		322	119	158
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		2,168	2,857	2,839
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		51	73	145
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		592	440	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		1,015	966	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		598	497	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		22	22	0
Commercial real estate | Mixed use and other
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		10,507	27,418	21,777
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		12,694	27,565	24,076
Impaired Financing Receivable, Related Allowance		1,847	2,111	2,240
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		10,557	28,474	21,483
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		290	551	1,017
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		11,683	5,330	7,985
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		12,008	7,842	8,804
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		12,427	5,875	9,533
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		266	218	449
Home equity
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		1,673	1,562	1,946
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		1,728	1,616	2,055
Impaired Financing Receivable, Related Allowance		808	636	475
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		1,680	1,567	1,995
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		34	30	80
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		4,236	4,468	4,453
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		5,697	6,553	6,172
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		4,320	4,842	4,666
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		118	138	256
Residential real estate
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		6,945	5,997	5,467
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		7,138	6,372	5,600
Impaired Financing Receivable, Related Allowance		1,363	457	606
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		6,963	5,914	5,399
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		137	140	241
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		13,258	12,422	12,640
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		14,961	15,538	14,334
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		13,553	12,836	12,682
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		294	295	595
Premium finance receivables | Commercial insurance loans
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, Related Allowance		0	0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		0	0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		0	0	0
Premium finance receivables | Life insurance loans
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, Related Allowance		0	0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		0	0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		0	0	0
Premium finance receivables | PCI - life insurance loans
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, Related Allowance		0	0	0
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		0	0	0
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		0	0	0
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		0	0	0
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		0	0	0
Consumer and other
Financing Receivable, Impaired [Line Items]
Impaired Financing Receivable, with Related Allowance, Recorded Investment		180	304	211
Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance		245	364	213
Impaired Financing Receivable, Related Allowance		44	102	26
Impaired Financing Receivable, with Related Allowance, Average Recorded Investment		190	308	214
Impaired Financing Receivable, with Related Allowance, Interest Income Recognized		6	8	10
Impaired Financing Receivable, with No Related Allowance, Recorded Investment		238	1,256	161
Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance		267	1,775	222
Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment		241	1,260	173
Impaired Financing Receivable, with No Related Allowance, Interest Income Recognized		$ 7	$ 53	$ 11

[1] These impaired loans require an allowance for loan losses because the estimated fair value of the loans or related collateral is less than the recorded investment in the loans.

[2] Impaired loans are considered by the Company to be non-accrual loans, TDRs or loans with principal and/or interest at risk, even if the loan is current with all payments of principal and interest.