LOANS HELD FOR INVESTMENT - Reconciliation of the Par Value of Loans Acquired in the Santander Acquisition with te Purchase Price (Detail) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($)
Allowance established for acquired PCD loans	$ 28,744
Residential Portfolio Segment [Member]
Allowance established for acquired PCD loans	12,739
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Allowance established for acquired PCD loans	1,830
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Allowance established for acquired PCD loans	9,723
Commercial Portfolio Segment [Member] | Construction Loans [Member]
Allowance established for acquired PCD loans	0
Consumer Portfolio Segment [Member]
Allowance established for acquired PCD loans	$ 4,452