SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Other Operating items, net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Other operating items, net	$ 7,115	$ 4,929	$ 6,711
Professional service fees	7,300	5,100	1,600
Gain (loss) on disposition of assets	100	(100)
Litigation proceeds		300
Insurance claim proceeds	$ 100	100
Pre-opening expenses relating to the Monarch Black Hawk Expansion project			2,800
Colorado legislation lobbying expenses			1,400
Equipment, supplies and employee testing expenses directly attributable to the pandemic for reopening of the properties and incremental to normal operations		$ 100	700
Write off of unamortized debt issuance costs			95
Unamortized debt issuance cost write off and loss on disposal of assets			$ 200