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VARIABLE INTEREST ENTITIES - Narrative (Details) $ in Thousands		12 Months Ended
	Jan. 28, 2021 USD ($)	Dec. 31, 2021 USD ($) loan	Dec. 31, 2020 USD ($) loan	Jan. 11, 2019 USD ($)	Mar. 31, 2017 USD ($)
Variable Interest Entity [Line Items]
Debt commitment		$ 1,041,157
Financing receivable, unpaid principal balance		105,400	$ 6,400
Loans held for investment		2,414,383	1,815,219
Sale of common stock		204,779	$ 73,232
Credit risk, financial instrument, maximum exposure		238,200
ACRE Commercial Mortgage 2021-FL4 Ltd. and ACRE Commercial Mortgage 2021-FL4 LLC \| Preferred Stock
Variable Interest Entity [Line Items]
Sale of common stock	$ 64,300
ACRE Commercial Mortgage 2021-FL4 Ltd. and ACRE Commercial Mortgage 2021-FL4 LLC \| Preferred Stock \| Wholly Owned Subsidiary To Parent Company
Variable Interest Entity [Line Items]
Sale of common stock		$ 64,300
Floating Rate Notes, Weighted Average Coupon Rate, LIBOR Plus 1.85%
Variable Interest Entity [Line Items]
Number of properties collateralized for mortgage loan \| loan		16	15
Receivables related to repayments of outstanding principal		$ 451,600	$ 550,600
Secured, Floating Rate Notes \| ACRE Commercial Mortgage 2021-FL4 Ltd. and ACRE Commercial Mortgage 2021-FL4 LLC
Variable Interest Entity [Line Items]
Aggregate principal amount	$ 603,000
Secured, Floating Rate Notes \| ACRE Commercial Mortgage 2021-FL4 Ltd. and ACRE Commercial Mortgage 2021-FL4 LLC \| Wholly Owned Subsidiary To Parent Company
Variable Interest Entity [Line Items]
Aggregate principal amount		62,500
Collateral amount		126,800
Repayments of debt		$ 121,200
FL4 Mortgage Assets
Variable Interest Entity [Line Items]
Number of properties collateralized for mortgage loan \| loan		17
Receivables related to repayments of outstanding principal		$ 522,800
Financing receivable, unpaid principal balance		23,200
Parent Company \| Offered Certificates
Variable Interest Entity [Line Items]
Preferred equity fully funded amount		52,900
Parent Company \| Secured funding agreements
Variable Interest Entity [Line Items]
Loans held for investment		111,400
Holdco \| Mortgaged Assets
Variable Interest Entity [Line Items]
Principal amount of certificates retained by wholly owned subsidiary of the entity		$ 58,500
Wells Fargo Facility \| Notes Payable
Variable Interest Entity [Line Items]
Debt commitment					$ 308,800
Wells Fargo Facility \| Notes Payable \| 2019 FL3 CLO Securitization
Variable Interest Entity [Line Items]
Debt commitment				$ 504,100
Wells Fargo Facility \| Collateralized Loan Obligations
Variable Interest Entity [Line Items]
Debt commitment					$ 32,400
Wells Fargo Facility \| Collateralized Loan Obligations \| 2019 FL3 CLO Securitization
Variable Interest Entity [Line Items]
Debt commitment				$ 52,900