EQUITY AWARDS - Schedule of Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
Number of Shares
Outstanding at beginning of year (in shares)	506,200	508,000	508,000
Effect of 10% stock dividend (in shares)	50,770
Granted (in shares)	24,500	23,000
Exercised (in shares)	(24,250)	(3,000)
Forfeited (in shares)	(10,000)	(24,400)
Balance (in shares)	547,220	503,600	506,200	508,000
Exercisable
Outstanding (in shares)	296,922	260,880
Weighted-average exercise price (in USD per share)	$ 23.49	$ 25.26
Weighted-average remaining contractual life in years	4 years 7 months 20 days	5 years 3 days
Aggregate intrinsic value	$ 3,938	$ 7
Weighted-Average Exercise Price
Outstanding at beginning of year (in USD per share)	$ 26.81	$ 26.68	$ 26.68
Granted (in USD per share)	33.37	29.00
Exercised (in USD per share)	21.74	24.00
Forfeited (in USD per share)	28.54	31.72
Balance (in USD per share)	$ 24.81	$ 26.55	$ 26.81	$ 26.68
Weighted-Average Remaining Contractual Life in Years
Outstanding	5 years 10 months 17 days	6 years 25 days	5 years 9 months 25 days	6 years 2 months 26 days
Granted	9 years 10 months 9 days	9 years 10 months 2 days
Exercised	3 years 3 months 10 days	2 years 6 months 14 days
Forfeited	5 years 11 months 19 days	8 years 5 months 15 days
Aggregate Intrinsic Value
Outstanding	$ 1,805	$ 3,159	$ 3,159
Granted	83	11
Exercised	364	0
Forfeited	82	0
Outstanding	$ 6,532	$ 21	$ 1,805	$ 3,159