FEDERAL HOME LOAN BANK ADVANCES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
FEDERAL HOME LOAN BANK ADVANCES.
Average daily balance during the year	$ 284,719	$ 245,283
Average interest rate during the year (as a percent)	1.40%	1.86%
Maximum month-end balance during the year	$ 340,000	$ 435,000
Weighted average interest rate at year-end (as a percent)	0.35%	1.82%