CREDIT QUALITY ASSESSMENT - Collateral dependent loans individually evaluated for credit loss (Detail) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	$ 25,823	$ 15,333
Allowance related to loans evaluated individually	8,263	5,501
Loans individually evaluated for credit loss without an allowance	30,299	9,440
Total individually evaluated collateral dependent loans	56,122	$ 24,773
Total unpaid contractual principal balance	75,551
Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	22,057
Loans individually evaluated for credit loss without an allowance	25,618
Total individually evaluated collateral dependent loans	47,675
Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	2,828
Loans individually evaluated for credit loss without an allowance	2,765
Total individually evaluated collateral dependent loans	5,593
Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	938
Loans individually evaluated for credit loss without an allowance	1,916
Total individually evaluated collateral dependent loans	2,854
Commercial real estate: | Commercial investor real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	14,991
Allowance related to loans evaluated individually	2,537
Loans individually evaluated for credit loss without an allowance	12,517
Total individually evaluated collateral dependent loans	27,508
Total unpaid contractual principal balance	33,452
Commercial real estate: | Commercial investor real estate | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	14,267
Loans individually evaluated for credit loss without an allowance	11,417
Total individually evaluated collateral dependent loans	25,684
Commercial real estate: | Commercial investor real estate | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	724
Loans individually evaluated for credit loss without an allowance	376
Total individually evaluated collateral dependent loans	1,100
Commercial real estate: | Commercial investor real estate | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	724
Total individually evaluated collateral dependent loans	724
Commercial real estate: | Commercial owner-occupied real estate
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	853
Allowance related to loans evaluated individually	22
Loans individually evaluated for credit loss without an allowance	5,658
Total individually evaluated collateral dependent loans	6,511
Total unpaid contractual principal balance	10,203
Commercial real estate: | Commercial owner-occupied real estate | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	4,194
Total individually evaluated collateral dependent loans	4,194
Commercial real estate: | Commercial owner-occupied real estate | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	853
Loans individually evaluated for credit loss without an allowance	1,464
Total individually evaluated collateral dependent loans	2,317
Commercial real estate: | Commercial owner-occupied real estate | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	0
Commercial real estate: | Commercial AD&C
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	1,678
Allowance related to loans evaluated individually	603
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	1,678
Total unpaid contractual principal balance	1,678
Commercial real estate: | Commercial AD&C | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	1,678
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	1,678
Commercial real estate: | Commercial AD&C | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	0
Commercial real estate: | Commercial AD&C | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	0
Commercial Business
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	8,301
Allowance related to loans evaluated individually	5,101
Loans individually evaluated for credit loss without an allowance	10,427
Total individually evaluated collateral dependent loans	18,728
Total unpaid contractual principal balance	27,171
Commercial Business | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	6,112
Loans individually evaluated for credit loss without an allowance	10,007
Total individually evaluated collateral dependent loans	16,119
Commercial Business | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	1,251
Loans individually evaluated for credit loss without an allowance	289
Total individually evaluated collateral dependent loans	1,540
Commercial Business | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	938
Loans individually evaluated for credit loss without an allowance	131
Total individually evaluated collateral dependent loans	1,069
Residential real estate: | Residential mortgage
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Allowance related to loans evaluated individually	0
Loans individually evaluated for credit loss without an allowance	1,333
Total individually evaluated collateral dependent loans	1,333
Total unpaid contractual principal balance	2,683
Residential real estate: | Residential mortgage | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	0
Residential real estate: | Residential mortgage | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	272
Total individually evaluated collateral dependent loans	272
Residential real estate: | Residential mortgage | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	1,061
Total individually evaluated collateral dependent loans	1,061
Residential real estate: | Residential construction
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Allowance related to loans evaluated individually	0
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	0
Total unpaid contractual principal balance	0
Residential real estate: | Residential construction | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	0
Residential real estate: | Residential construction | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	0
Residential real estate: | Residential construction | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	0
Consumer
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Allowance related to loans evaluated individually	0
Loans individually evaluated for credit loss without an allowance	364
Total individually evaluated collateral dependent loans	364
Total unpaid contractual principal balance	364
Consumer | Non-accruing
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	0
Consumer | Non-accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	364
Total individually evaluated collateral dependent loans	364
Consumer | Accruing | Restructured
Financing Receivable, Allowance for Credit Loss [Line Items]
Loans individually evaluated for credit loss with an allowance	0
Loans individually evaluated for credit loss without an allowance	0
Total individually evaluated collateral dependent loans	$ 0