Collateralized Loan Obligations - Schedule of Assets and Liabilities Included in Consolidated Balance Sheet (Details) - USD ($) $ in Thousands		Dec. 31, 2021	Dec. 31, 2020
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Commercial real estate loans, held-for-investment		$ 6,316,733	$ 4,844,534
Less: Allowance for credit losses		(22,244)	(59,801)
Commercial real estate loans, held-for-investment, net		6,294,489	4,784,733
Accrued interest receivable		15,241	15,412
Other assets	[1]	7,916	20,984
Total Assets		6,703,239	4,965,612
Collateralized loan obligations, net		1,087,976	810,000
Accrued interest payable		6,627	5,381
Accounts payable, accrued expenses and other liabilities	[2]	7,521	4,823
Total Liabilities		5,341,658	3,920,206
Collateralized Loan Obligations
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Commercial real estate loans, held-for-investment, net		1,246,000	1,000,000
Collateralized Loan Obligations | Primary Beneficiary
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Cash		54,000	0
Collateralized Loan Obligations | Primary Beneficiary | KREF 2021-FL2
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Cash		54,000
Commercial real estate loans, held-for-investment		1,246,000
Less: Allowance for credit losses		(3,255)
Commercial real estate loans, held-for-investment, net		1,242,745
Accrued interest receivable		3,091
Other assets		766
Total Assets		1,300,602
Collateralized loan obligations, net		1,087,976
Accrued interest payable		852
Accounts payable, accrued expenses and other liabilities		0
Total Liabilities		1,088,828
Unamortized debt issuance costs		$ 7,300
Collateralized Loan Obligations | Primary Beneficiary | KREF 2018-FL1
Assets and Associated Liabilities of Transfers Accounted for as Secured Borrowings [Line Items]
Cash			0
Commercial real estate loans, held-for-investment			1,000,483
Less: Allowance for credit losses			(2,669)
Commercial real estate loans, held-for-investment, net			997,814
Accrued interest receivable			3,075
Other assets			5
Total Assets			1,000,894
Collateralized loan obligations, net			810,000
Accrued interest payable			668
Accounts payable, accrued expenses and other liabilities			72
Total Liabilities			$ 810,740

[1] Includes $0.0 million and $15.9 million of loan repayment proceeds held by servicer and receivable by KREF, and $2.3 million and $0.0 million of restricted cash as of December 31, 2021 and 2020, respectively.

[2] Includes $1.5 million and $0.9 million of expected loss reserve for unfunded loan commitments as of December 31, 2021 and 2020, respectively.