Related Party Transactions - Additional Information (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Related Party Transaction [Line Items]
Annual base management fee percentage	1.50%
Base management fee payable to affiliate	$ 9,983,000	$ 9,849,000
Management fee, description	Effective October 1, 2015, the Manager earns a base management fee in an amount equal to 1.50% per annum of Stockholders’ Equity. Management fees are reduced by the Company’s pro rata share of any management fees and incentive fees (if incentive fees are not incurred by the Company) paid to the Manager by CMTG/TT. Management fees are paid quarterly, in arrears. Management fees of $10.0 million and $9.8 million were accrued and were included in management fee payable – affiliate, in the consolidated balance sheets at December 31, 2021 and 2020
Incentive fee rate	20.00%
Minimum percentage of incentive fee to be paid in return on stockholders’ equity	7.00%
Incentive fees, description	The Manager is entitled to an incentive fee equal to 20% of the excess of the Company’s Core Earnings on a rolling four-quarter basis, as defined in the Management Agreement, over a 7.00% return on Stockholders’ Equity, as defined in the Management Agreement of the Company. Incentive fees are reduced by the Company’s pro rata share of any incentive fees paid to the Manager by CMTG/TT.
Incentive fee payable - affiliate	$ 0	187,000
Termination fee, description	If the Company elects to terminate the Management Agreement, the Company is required to pay the Manager a termination fee equal to three times the sum of the average annual base management and incentive fees paid by the Company over the prior two years and the average annual incentive fee paid by the Company over the prior two years
Outstanding principal balance	$ 54,000,000.0
Loan commitment	141,100,000
Reimbursements
Related Party Transaction [Line Items]
General and administrative expense	$ 0	$ 81,000,000	$ 200
C M T G T T Mortgage R E I T L L C
Related Party Transaction [Line Items]
Incentive fee rate	3.33%
Minimum percentage of incentive fee to be paid in return on stockholders’ equity	7.00%