LOANS HELD FOR INVESTMENT - Corporation's TDR Activity (Detail) - TDR - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Financing Receivable Modifications [Line Items]
Beginning Balance of TDRs	$ 479,196	$ 487,997	$ 582,647
New TDRs	34,216	36,319	63,433
Increases to existing TDRs	94	6,009	1,840
Charge-offs post modification	(17,434)	(11,122)	(10,342)
Sales, net of charge-offs	(17,492)	0	0
Foreclosures	(3,117)	(2,015)	(12,872)
Removed from the TDR classification	(8,001)	0	0
Paid-off, partial payments and other	(52,724)	(37,992)	(136,709)
Ending balance of TDRs	$ 414,738	$ 479,196	$ 487,997