FAIR VALUES OF FINANCIAL INSTRUMENTS - Reconciliation of Assets Measured at Fair Value on Recurring Basis (Detail) - Recurring - Significant Unobservable Inputs (Level 3) - U.S. government agency and U.S. government sponsored enterprise residential mortgage-backed securities - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of period	$ 17,127	$ 23,069	$ 19,233	$ 25,040
Total gains (losses) (realized/unrealized):
Included in earnings—fair value adjustment	22	(6)	(1,369)	(3)
Additions	0	0	0	0
Sales, settlements, and other	(464)	(1,988)	(1,179)	(3,962)
Balance at end of period	$ 16,685	$ 21,075	$ 16,685	$ 21,075