CREDIT QUALITY ASSESSMENT - Information on the credit quality of loan portfolio under the new CECL (Detail) $ in Thousands	9 Months Ended
	Sep. 30, 2020 USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 38,632
Loans placed on non-accrual	30,500
Commercial real estate: | Commercial investor real estate
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	8,437
Commercial real estate: | Commercial owner-occupied real estate
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	4,148
Commercial real estate: | Commercial AD&C
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	829
Commercial Business
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	8,450
Residential real estate: | Residential mortgage
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	12,661
Residential real estate: | Residential construction
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	0
Consumer
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	4,107
Non-accrual status
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	38,632
PCD loans designed as non-accrual	13,084
Loans placed on non-accrual	30,551
Non-accrual balances transferred to OREO	0
Non-accrual balances charged-off	(881)
Net payments or draws	(7,989)
Non-accrual loans brought current	(1,976)
Balance at end of period	71,421
Non-accrual status | Commercial real estate: | Commercial investor real estate
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	8,437
PCD loans designed as non-accrual	9,544
Loans placed on non-accrual	9,437
Non-accrual balances transferred to OREO	0
Non-accrual balances charged-off	(23)
Net payments or draws	(611)
Non-accrual loans brought current	0
Balance at end of period	26,784
Non-accrual status | Commercial real estate: | Commercial owner-occupied real estate
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	4,148
PCD loans designed as non-accrual	0
Loans placed on non-accrual	3,425
Non-accrual balances transferred to OREO	0
Non-accrual balances charged-off	0
Net payments or draws	(961)
Non-accrual loans brought current	(101)
Balance at end of period	6,511
Non-accrual status | Commercial real estate: | Commercial AD&C
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	829
PCD loans designed as non-accrual	0
Loans placed on non-accrual	2,128
Non-accrual balances transferred to OREO	0
Non-accrual balances charged-off	0
Net payments or draws	(1,279)
Non-accrual loans brought current	0
Balance at end of period	1,678
Non-accrual status | Commercial Business
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	8,450
PCD loans designed as non-accrual	2,539
Loans placed on non-accrual	10,988
Non-accrual balances transferred to OREO	0
Non-accrual balances charged-off	(386)
Net payments or draws	(3,052)
Non-accrual loans brought current	(880)
Balance at end of period	17,659
Non-accrual status | Residential real estate: | Residential mortgage
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	12,661
PCD loans designed as non-accrual	8
Loans placed on non-accrual	896
Non-accrual balances transferred to OREO	0
Non-accrual balances charged-off	(351)
Net payments or draws	(1,058)
Non-accrual loans brought current	(860)
Balance at end of period	11,296
Non-accrual status | Residential real estate: | Residential construction
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	0
PCD loans designed as non-accrual	0
Loans placed on non-accrual	0
Non-accrual balances transferred to OREO	0
Non-accrual balances charged-off	0
Net payments or draws	0
Non-accrual loans brought current	0
Balance at end of period	0
Non-accrual status | Consumer
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	4,107
PCD loans designed as non-accrual	993
Loans placed on non-accrual	3,677
Non-accrual balances transferred to OREO	0
Non-accrual balances charged-off	(121)
Net payments or draws	(1,028)
Non-accrual loans brought current	(135)
Balance at end of period	$ 7,493