Allowance for Loan Losses, Allowance for Losses on Lending-Related Commitments and Impaired Loans (Schedule of Aging of the Company's Loan Portfolio) (Detail) - USD ($) $ in Thousands		Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		$ 81,856	$ 78,950	$ 80,698
90+ days and still accruing		48,064	41,872	43,585
Current		17,308,727	16,993,266	14,917,238
Loans, net of unearned income, excluding covered loans		17,446,413	17,118,117	14,953,059
Nonaccrual		76,532	73,072	73,619
90+ days and still accruing		40,069	34,537	27,151
Current		17,190,038	16,864,283	14,737,743
Covered loans, Nonaccrual		5,324	5,878	7,079
Covered loans, 90 plus days and still accruing		7,995	7,335	16,434
Covered loans, Current		118,689	128,983	179,495
Covered loans		138,848	148,673	209,694
Total loans		17,585,261	17,266,790	15,162,753
60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		19,603	42,806	26,769
60-89 days past due		19,254	42,103	26,211
Covered loans, 60-89 days past due		349	703	558
30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		127,011	109,896	94,463
30-59 days past due		120,520	104,122	88,335
Covered loans, 30-59 days past due		6,491	5,774	6,128
Commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		12,373	12,712	5,586
90+ days and still accruing		2,231	1,433	612
Current		4,827,896	4,666,927	4,177,491
Loans, net of unearned income, excluding covered loans		4,890,246	4,713,909	4,211,932
Commercial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		3,345	11,361	5,112
Commercial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		44,401	21,476	23,131
Commercial | Commercial, industrial and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		12,370	12,704	5,586
90+ days and still accruing		338	6	0
Current		3,363,011	3,226,139	2,779,781
Loans, net of unearned income, excluding covered loans		3,404,555	3,258,528	2,807,752
Commercial | Commercial, industrial and other | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		3,228	6,749	5,047
Commercial | Commercial, industrial and other | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		25,608	12,930	17,338
Commercial | Franchise
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		0	0	0
90+ days and still accruing		0	0	0
Current		273,158	245,228	225,305
Loans, net of unearned income, excluding covered loans		274,558	245,228	225,762
Commercial | Franchise | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	0	0
Commercial | Franchise | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		1,400	0	457
Commercial | Mortgage warehouse lines of credit
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		0	0	0
90+ days and still accruing		0	0	0
Current		192,244	222,806	186,372
Loans, net of unearned income, excluding covered loans		193,735	222,806	186,372
Commercial | Mortgage warehouse lines of credit | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	0	0
Commercial | Mortgage warehouse lines of credit | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		1,491	0	0
Commercial | Asset-based lending
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		3	8	0
90+ days and still accruing		0	0	0
Current		737,184	736,968	805,866
Loans, net of unearned income, excluding covered loans		747,901	742,684	810,685
Commercial | Asset-based lending | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		117	3,864	0
Commercial | Asset-based lending | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		10,597	1,844	4,819
Commercial | Leases
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		0	0	0
90+ days and still accruing		0	535	0
Current		244,241	220,599	171,432
Loans, net of unearned income, excluding covered loans		249,418	226,074	172,014
Commercial | Leases | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	748	65
Commercial | Leases | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		5,177	4,192	517
Commercial | PCI - commercial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	[1]	0	0	0
90+ days and still accruing	[1]	1,893	892	612
Current	[1]	18,058	15,187	8,735
Loans, net of unearned income, excluding covered loans	[1],[2]	20,079	18,589	9,347
Commercial | PCI - commercial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	[1]	0	0	0
Commercial | PCI - commercial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	[1]	128	2,510	0
Commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		26,996	26,645	29,982
90+ days and still accruing		25,998	22,111	18,120
Current		5,633,284	5,424,863	4,628,193
Loans, net of unearned income, excluding covered loans		5,737,959	5,529,289	4,710,486
Commercial real estate | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		5,792	16,427	6,072
Commercial real estate | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		45,889	39,243	28,119
Commercial real estate | Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		273	306	0
90+ days and still accruing		0	0	0
Current		389,026	355,338	255,835
Loans, net of unearned income, excluding covered loans		391,322	358,660	256,827
Commercial real estate | Construction | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	1,371	0
Commercial real estate | Construction | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		2,023	1,645	992
Commercial real estate | Land
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		1,746	1,751	2,646
90+ days and still accruing		0	0	0
Current		93,834	76,546	84,454
Loans, net of unearned income, excluding covered loans		95,580	78,417	89,042
Commercial real estate | Land | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	0	0
Commercial real estate | Land | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	120	1,942
Commercial real estate | Office
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		7,729	4,619	8,243
90+ days and still accruing		1,260	0	0
Current		865,954	853,801	731,568
Loans, net of unearned income, excluding covered loans		888,494	863,001	743,126
Commercial real estate | Office | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		980	764	171
Commercial real estate | Office | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		12,571	3,817	3,144
Commercial real estate | Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		10,960	9,564	3,496
90+ days and still accruing		0	0	0
Current		728,061	715,207	599,050
Loans, net of unearned income, excluding covered loans		742,956	727,648	604,326
Commercial real estate | Industrial | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		0	1,868	61
Commercial real estate | Industrial | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		3,935	1,009	1,719
Commercial real estate | Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		1,633	1,760	4,975
90+ days and still accruing		0	0	0
Current		890,780	863,887	734,990
Loans, net of unearned income, excluding covered loans		897,467	868,399	742,527
Commercial real estate | Retail | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		2,397	442	0
Commercial real estate | Retail | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		2,657	2,310	2,562
Commercial real estate | Multi-family
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		287	1,954	1,750
90+ days and still accruing		0	0	0
Current		760,084	733,230	649,589
Loans, net of unearned income, excluding covered loans		763,073	742,349	655,403
Commercial real estate | Multi-family | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		655	597	393
Commercial real estate | Multi-family | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		2,047	6,568	3,671
Commercial real estate | Mixed use and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		4,368	6,691	8,872
90+ days and still accruing		0	0	0
Current		1,778,850	1,712,187	1,532,036
Loans, net of unearned income, excluding covered loans		1,795,717	1,732,816	1,552,563
Commercial real estate | Mixed use and other | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		187	6,723	808
Commercial real estate | Mixed use and other | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		12,312	7,215	10,847
Commercial real estate | PCI - commercial real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	[1]	0	0	0
90+ days and still accruing	[1]	24,738	22,111	18,120
Current	[1]	126,695	114,667	40,671
Loans, net of unearned income, excluding covered loans	[1],[2]	163,350	157,999	66,672
Commercial real estate | PCI - commercial real estate | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	[1]	1,573	4,662	4,639
Commercial real estate | PCI - commercial real estate | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	[1]	10,344	16,559	3,242
Home equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		9,365	6,848	7,665
90+ days and still accruing		0	0	0
Current		759,712	770,421	698,100
Loans, net of unearned income, excluding covered loans		774,342	784,675	709,283
Home equity | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		791	1,889	693
Home equity | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		4,474	5,517	2,825
Residential real estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		11,964	12,043	14,248
90+ days and still accruing		406	488	266
Current		603,372	588,851	471,839
Loans, net of unearned income, excluding covered loans		626,043	607,451	495,925
Residential real estate | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		193	2,166	753
Residential real estate | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		10,108	3,903	8,819
Premium finance receivables | Commercial insurance loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		15,350	14,561	15,902
90+ days and still accruing		9,548	10,294	8,062
Current		2,275,420	2,321,786	2,271,791
Loans, net of unearned income, excluding covered loans		2,320,987	2,374,921	2,319,623
Premium finance receivables | Commercial insurance loans | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		5,583	6,624	4,476
Premium finance receivables | Commercial insurance loans | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		15,086	21,656	19,392
Premium finance receivables | Life insurance loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		0	0	0
90+ days and still accruing		1,641	0	0
Current		2,675,525	2,578,632	1,972,197
Loans, net of unearned income, excluding covered loans		2,680,796	2,593,204	1,986,606
Premium finance receivables | Life insurance loans | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		3,432	3,432	8,994
Premium finance receivables | Life insurance loans | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		198	11,140	5,415
Premium finance receivables | PCI - life insurance loans
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual	[1]	0	0	0
90+ days and still accruing	[1]	0	0	0
Current	[1]	296,138	368,292	389,048
Loans, net of unearned income, excluding covered loans	[1],[2]	296,138	368,292	389,048
Premium finance receivables | PCI - life insurance loans | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	[1]	0	0	0
Premium finance receivables | PCI - life insurance loans | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	[1]	0	0	0
Consumer and other
Financing Receivable, Recorded Investment, Past Due [Line Items]
Nonaccrual		484	263	236
90+ days and still accruing		245	211	91
Current		118,691	144,511	129,084
Loans, net of unearned income, excluding covered loans		119,902	146,376	130,156
Consumer and other | 60-89 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		118	204	111
Consumer and other | 30-59 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due		$ 364	$ 1,187	$ 634

[1] PCI 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.

[2] PCI loans represent loans acquired with evidence of credit quality deterioration since origination, in accordance with ASC 310-30. See Note 6 - Loans for further discussion of these purchased loans.