EQUITY SECURITIES - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Summary of Investment Holdings [Line Items]
Capital stock par value	$ 100
Book value of investment in FHLB stock	$ 31,200	$ 34,100
Market-to-market gains (losses)	41,834	39,909	$ 32,742
Equity Securities [Member]
Summary of Investment Holdings [Line Items]
Equity Securities	1,500	1,400
Market-to-market gains (losses)	38	4	(9)
Equity Securities without Readily Determinable Fair Value, Amount	4,900	2,800
Investment in Federal Home Loan Bank Stock [Member]
Summary of Investment Holdings [Line Items]
Dividend income from FHLB stock	$ 2,000	$ 2,700	$ 2,100