Real Estate, net and Real Estate Held for Sale - Depreciation Expense (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Real Estate [Abstract]
Depreciation expense on real estate	$ 9.4	$ 20.7	$ 21.4	$ 40.6

Real Estate Investment Property, Depreciation Expense

No definition available.

Name:	clnc_RealEstateInvestmentPropertyDepreciationExpense
Namespace Prefix:	clnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration