EMPLOYEE BENEFITS, Employee Health Benefits (Details) - Employee Health Benefits [Member]	12 Months Ended
	Dec. 31, 2020 USD ($) h	Dec. 31, 2019 USD ($)
Employee Health Benefits [Abstract]
Waiting period to be eligible for non-officers	60 days
Welfare benefit expense	$ 4,400,000	$ 4,800,000
Accrued benefit obligations	823,000	$ 464,000
Annual limit for stop loss amount per participant	$ 100,000
Minimum [Member]
Employee Health Benefits [Abstract]
Number of working hours required per week to be eligible to cover under self-insured welfare benefit plan | h	30