Loans and Leases and the Allowance for Credit Losses - Loan Modification Activities that were Considered Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022 USD ($) Modification	Jun. 30, 2021 USD ($) Modification	Jun. 30, 2022 USD ($) Modification	Jun. 30, 2021 USD ($) Modification
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	917	492	1,852	1,347
Pre-modification Recorded Investment	$ 77,353	$ 254,305	$ 138,809	$ 385,937
Loans and leases, net of unearned discount	79,422	252,836	141,716	382,797
Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	66,289	54,746	112,467	140,262
Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	9		9
Other [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	700	28,578	2,855	30,792
Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	$ 12,424	$ 169,512	$ 26,385	$ 211,743
Commercial, Financial, Leasing, etc. [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	40	89	77	182
Pre-modification Recorded Investment	$ 36,983	$ 70,749	$ 46,986	$ 124,482
Loans and leases, net of unearned discount	38,186	70,448	47,940	123,605
Commercial, Financial, Leasing, etc. [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	31,514	11,439	38,434	36,092
Commercial, Financial, Leasing, etc. [Member] | Interest Rate Reduction [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	9		9
Commercial, Financial, Leasing, etc. [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	700	222	754	222
Commercial, Financial, Leasing, etc. [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	$ 5,963	$ 58,787	$ 8,743	$ 87,291
Commercial Real Estate [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	13	35	30	68
Pre-modification Recorded Investment	$ 2,816	$ 143,141	$ 10,398	$ 170,011
Loans and leases, net of unearned discount	2,784	142,161	10,116	167,957
Commercial Real Estate [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	1,454	7,370	5,830	18,530
Commercial Real Estate [Member] | Other [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount		28,356	2,101	30,570
Commercial Real Estate [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	$ 1,330	$ 106,435	$ 2,185	$ 118,857
Other Commercial Construction [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		3		3
Pre-modification Recorded Investment		$ 542		$ 542
Loans and leases, net of unearned discount		$ 532		532
Other Commercial Construction [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount				$ 532
Residential [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	67	117	164	240
Pre-modification Recorded Investment	$ 18,481	$ 34,041	$ 42,532	$ 73,624
Loans and leases, net of unearned discount	19,322	33,863	44,726	73,537
Residential [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	14,284	29,573	29,727	68,130
Residential [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	$ 5,038	$ 4,290	$ 14,999	$ 5,407
Residential Limited Documentation [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification		3	5	13
Pre-modification Recorded Investment		$ 405	$ 1,076	$ 1,521
Loans and leases, net of unearned discount		405	1,087	1,464
Residential Limited Documentation [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount		$ 405	894	$ 1,464
Residential Limited Documentation [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount			$ 193
Home Equity Lines and Loans [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	33	16	68	42
Pre-modification Recorded Investment	$ 2,633	$ 1,970	$ 4,783	$ 3,685
Loans and leases, net of unearned discount	2,690	1,970	4,850	3,630
Home Equity Lines and Loans [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	2,597	$ 1,970	4,585	3,456
Home Equity Lines and Loans [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	$ 93		$ 265	$ 174
Recreational Finance [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	170	34	347	106
Pre-modification Recorded Investment	$ 6,204	$ 1,119	$ 12,201	$ 3,331
Loans and leases, net of unearned discount	6,204	1,119	12,194	3,331
Recreational Finance [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	$ 6,204	$ 1,119	$ 12,194	$ 3,331
Automobile [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	529	94	1,063	370
Pre-modification Recorded Investment	$ 9,771	$ 1,502	$ 20,034	$ 6,471
Loans and leases, net of unearned discount	9,771	1,502	20,004	6,471
Automobile [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	$ 9,771	$ 1,502	$ 20,004	6,457
Automobile [Member] | Combination of Concession Types [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount				$ 14
Other [Member]
Financing Receivable, Modifications [Line Items]
Number of modifications | Modification	65	101	98	323
Pre-modification Recorded Investment	$ 465	$ 836	$ 799	$ 2,270
Loans and leases, net of unearned discount	465	836	799	2,270
Other [Member] | Principal Deferral [Member]
Financing Receivable, Modifications [Line Items]
Loans and leases, net of unearned discount	$ 465	$ 836	$ 799	$ 2,270