Derivatives - Narrative (Details) $ in Millions	Sep. 30, 2019 USD ($)
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Cash collateral for the derivative contracts	$ 22.1

Cash Collateral For Derivatives Held By Counterparties

No definition available.

Name:	clnc_CashCollateralForDerivativesHeldByCounterparties
Namespace Prefix:	clnc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant