LOAN PORTFOLIO - Selected Information on TDRs Includes Recorded Investment by Loan Class and Modification Type (Detail) - Entity Loan Modification Program [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 589,795	$ 582,647	$ 572,376	$ 587,219
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	72,348	74,921
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	155,333	137,949
Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	28,300
Other Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	328,745	333,902
Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	9,723	10,382
Construction Loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	5,100
Construction Loans [Member] | Commercial Portfolio Segment [Member] | Residential [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	532	762
Construction Loans [Member] | Commercial Portfolio Segment [Member] | Commercial [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Construction Loans [Member] | Commercial Portfolio Segment [Member] | Land [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	4,582	4,765
Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	16,960	18,031
Finance leases loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,572	1,935
Interest rate below market [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	27,793	28,771
Interest rate below market [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	644	664
Interest rate below market [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	3,919	3,966
Interest rate below market [Member] | Other Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	21,898	22,729
Interest rate below market [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,305	1,396
Interest rate below market [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Residential [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Interest rate below market [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Commercial [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Interest rate below market [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Land [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	27	16
Interest rate below market [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Interest rate below market [Member] | Finance leases loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Maturity or term extension [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	38,581	39,283
Maturity or term extension [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	19,249	19,769
Maturity or term extension [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,819	2,005
Maturity or term extension [Member] | Other Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	11,827	11,586
Maturity or term extension [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,257	1,236
Maturity or term extension [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Residential [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	532	545
Maturity or term extension [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Commercial [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Maturity or term extension [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Land [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	2,447	2,524
Maturity or term extension [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,368	1,517
Maturity or term extension [Member] | Finance leases loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	82	101
Combination of reduction in interest rateand extension of maturity [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	385,338	394,235
Combination of reduction in interest rateand extension of maturity [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	13,092	13,323
Combination of reduction in interest rateand extension of maturity [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	120,363	122,709
Combination of reduction in interest rateand extension of maturity [Member] | Other Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	234,073	239,348
Combination of reduction in interest rateand extension of maturity [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	5,453	5,651
Combination of reduction in interest rateand extension of maturity [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Residential [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Combination of reduction in interest rateand extension of maturity [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Commercial [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Combination of reduction in interest rateand extension of maturity [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Land [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,866	1,933
Combination of reduction in interest rateand extension of maturity [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	9,448	10,085
Combination of reduction in interest rateand extension of maturity [Member] | Finance leases loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,043	1,186
Forgiveness of principal and/or interest [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	341	275
Forgiveness of principal and/or interest [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forgiveness of principal and/or interest [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forgiveness of principal and/or interest [Member] | Other Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forgiveness of principal and/or interest [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	341	275
Forgiveness of principal and/or interest [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Residential [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forgiveness of principal and/or interest [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Commercial [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forgiveness of principal and/or interest [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Land [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forgiveness of principal and/or interest [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forgiveness of principal and/or interest [Member] | Finance leases loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forbearance Agreement [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	21,464	2,818
Forbearance Agreement [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,262	2,673
Forbearance Agreement [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	20,059	0
Forbearance Agreement [Member] | Other Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	143	145
Forbearance Agreement [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forbearance Agreement [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Residential [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forbearance Agreement [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Commercial [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forbearance Agreement [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Land [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forbearance Agreement [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Forbearance Agreement [Member] | Finance leases loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Other Loan Modifications [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	116,278	117,265
Other Loan Modifications [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	38,101	38,492
Other Loan Modifications [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	9,173	9,269
Other Loan Modifications [Member] | Other Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	60,804	60,094
Other Loan Modifications [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	1,367	1,824
Other Loan Modifications [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Residential [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	217
Other Loan Modifications [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Commercial [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	0	0
Other Loan Modifications [Member] | Construction Loans [Member] | Commercial Portfolio Segment [Member] | Land [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	242	292
Other Loan Modifications [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	6,144	6,429
Other Loan Modifications [Member] | Finance leases loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Financing Receivable, Modifications, Recorded Investment	$ 447	$ 648