BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Redeemable Preferred Stock (Details)	3 Months Ended
Mar. 31, 2018
BASIS OF PRESENTATION AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Preferred stock, percentage of stated value	100.00%
Preferred stock redemption, trading days prior to redemption	20 days

Preferred Stock, Redemption Price, Consecutive Trading Days of Weighted Average Common Stock Price

No definition available.

Name:	cmct_PreferredStockRedemptionPriceConsecutiveTradingDaysofWeightedAverageCommonStockPrice
Namespace Prefix:	cmct_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration