SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Other Operating items, net (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Other operating items, net	$ 1,317,000	$ 754,000
Professional service fees		600,000
Equipment, supplies and employee testing expenses due to the COVID-19 pandemic		$ 100,000