Debt Obligations - Summary of Interest Expense and Amortization (Parenthetical) (Details) - USD ($)	12 Months Ended
Dec. 31, 2022	Dec. 31, 2021
Debt Disclosure [Abstract]
Amortization of financing costs included in Interest on debt related to real estate owned	$ 309,000	$ 56,000

Amortization of Financing Costs Included in Interest Expense on Debt Related To Real Estate Owned

No definition available.

Name:	cmtg_AmortizationOfFinancingCostsIncludedInInterestExpenseOnDebtRelatedToRealEstateOwned
Namespace Prefix:	cmtg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration