CREDIT QUALITY ASSESSMENT - Allowance for credit loss activity (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period	$ 165,367	$ 56,132	$ 56,132
Provision for credit losses	(34,708)	24,469	85,669
Loan charge-offs	(743)	(654)	(1,819)
Loan recoveries	445	108	1,012
Net charge-offs	(298)	(546)	(807)
Balance at period end	$ 130,361	85,800	165,367
Revision of Prior Period, Reclassification, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		2,762	2,762
Revision of Prior Period, Accounting Standards Update, Adjustment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Balance at beginning of period		$ 2,983	$ 2,983