SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Credit losses (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Reserve for gaming and non-gaming receivables	$ 0.1	$ 0.2

Amount of reserve for gaming and non-gaming receivables.

No definition available.

Name:	mcri_ReserveForGamingAndNonGamingReceivables
Namespace Prefix:	mcri_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration