Debt - Schedule of Debt (Details) kr in Billions	1 Months Ended	9 Months Ended
	Nov. 06, 2020 USD ($)	Sep. 30, 2020 USD ($) extension property debt_instrument	Sep. 30, 2020 NOK (kr) property	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
Principal amount		$ 2,556,443,000		$ 3,199,923,000
Carrying value		2,546,252,000		3,188,498,000
Mortgage and other notes payable, net		1,102,999,000		1,256,112,000
Net lease 2
Debt Instrument [Line Items]
Mortgage and other notes payable, net		$ 170,100,000	kr 1.6
Other real estate 10
Debt Instrument [Line Items]
Number of instruments | debt_instrument		2
Weighted average interest rate (in percentage)		3.53%	3.53%
Securitization bonds payable, net
Debt Instrument [Line Items]
Principal amount		$ 840,423,000		840,423,000
Carrying value		$ 834,621,000		833,153,000
Securitization bonds payable, net | Minimum
Debt Instrument [Line Items]
Initial debt term (in years)		2 years
Securitization bonds payable, net | Maximum
Debt Instrument [Line Items]
Initial debt term (in years)		3 years
Mortgage and other notes payable, net
Debt Instrument [Line Items]
Principal amount		$ 1,107,388,000		1,260,267,000
Carrying value		$ 1,102,999,000		1,256,112,000
Mortgage and other notes payable, net | Net lease 6 | Collateralized by a property in Company's Core Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.45%	4.45%
Principal amount		$ 23,780,000		24,117,000
Carrying value		23,780,000		24,117,000
Mortgage and other notes payable, net | Net lease 6 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Principal amount		1,439,000		1,658,000
Carrying value		$ 1,405,000		1,615,000
Mortgage and other notes payable, net | Net lease 6 | Collateralized by a property in Legacy, Non-Strategic Portfolio | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		2.15%
Mortgage and other notes payable, net | Net lease 5 | Collateralized by a property in Company's Core Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.08%	4.08%
Principal amount		$ 31,439,000		31,821,000
Carrying value		$ 31,189,000		31,539,000
Mortgage and other notes payable, net | Net lease 5 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.45%	4.45%
Principal amount		$ 3,373,000		3,422,000
Carrying value		3,290,000		3,329,000
Mortgage and other notes payable, net | Net lease 4 | Collateralized by a property in Company's Core Portfolio
Debt Instrument [Line Items]
Principal amount		0		74,916,000
Carrying value		$ 0		74,845,000
Mortgage and other notes payable, net | Net lease 4 | Collateralized by a property in Company's Core Portfolio | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		2.50%
Mortgage and other notes payable, net | Net lease 4 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.45%	4.45%
Principal amount		$ 7,272,000		7,384,000
Carrying value		$ 7,094,000		7,184,000
Mortgage and other notes payable, net | Net lease 3 | Collateralized by a property in Company's Core Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.77%	4.77%
Principal amount		$ 200,000,000		200,000,000
Carrying value		$ 198,583,000		198,521,000
Mortgage and other notes payable, net | Net lease 3 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.00%	4.00%
Principal amount		$ 12,308,000		12,450,000
Carrying value		$ 12,268,000		12,368,000
Mortgage and other notes payable, net | Net lease 1 | Collateralized by a property in Company's Core Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.31%	4.31%
Principal amount		$ 250,000,000		250,000,000
Carrying value		$ 247,270,000		246,961,000
Mortgage and other notes payable, net | Net lease 1 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.45%	4.45%
Principal amount		$ 18,315,000		18,579,000
Carrying value		$ 17,866,000		18,076,000
Mortgage and other notes payable, net | Net lease 1 | Collateralized by properties in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.38%	4.38%
Principal amount		$ 12,077,000		12,221,000
Carrying value		$ 11,639,000		11,758,000
Number of properties | property		3	3
Mortgage and other notes payable, net | Net lease 2 | Collateralized by a property in Company's Core Portfolio
Debt Instrument [Line Items]
Contractual interest rate		3.91%	3.91%
Principal amount		$ 170,112,000		181,952,000
Carrying value		$ 172,524,000		184,532,000
Mortgage and other notes payable, net | Other real estate 4 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.84%	4.84%
Principal amount		$ 42,383,000		42,925,000
Carrying value		$ 42,853,000		43,407,000
Debt term extension available (in years)		1 year
Mortgage and other notes payable, net | Other real estate 2 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.94%	4.94%
Principal amount		$ 0		42,443,000
Carrying value		$ 0		42,851,000
Mortgage and other notes payable, net | Other real estate 8 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		3.53%	3.53%
Principal amount		$ 22,880,000		15,819,000
Carrying value		$ 22,648,000		16,324,000
Mortgage and other notes payable, net | Other real estate 10 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		3.53%	3.53%
Principal amount		$ 12,480,000		11,744,000
Carrying value		$ 12,306,000		11,939,000
Mortgage and other notes payable, net | Other real estate 9 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		3.98%	3.98%
Principal amount		$ 23,543,000		23,885,000
Carrying value		$ 22,791,000		23,133,000
Mortgage and other notes payable, net | Other real estate 1 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.47%	4.47%
Principal amount		$ 107,317,000		108,719,000
Carrying value		$ 107,915,000		109,475,000
Mortgage and other notes payable, net | Other real estate 3 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Contractual interest rate		4.30%	4.30%
Principal amount		$ 74,134,000		75,256,000
Carrying value		73,548,000		74,554,000
Mortgage and other notes payable, net | Other real estate 5 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Principal amount		0		33,498,000
Carrying value		$ 0		32,801,000
Mortgage and other notes payable, net | Other real estate 5 | Collateralized by a property in Legacy, Non-Strategic Portfolio | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		4.00%
Mortgage and other notes payable, net | Other real estate 6 | Collateralized by a property in Legacy, Non-Strategic Portfolio
Debt Instrument [Line Items]
Principal amount		$ 22,788,000		21,500,000
Carrying value		$ 22,282,000		20,825,000
Number of optional extensions to initial maturity date | extension		2
Mortgage and other notes payable, net | Other real estate 6 | Collateralized by a property in Legacy, Non-Strategic Portfolio | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		2.95%
Mortgage and other notes payable, net | Loan 9
Debt Instrument [Line Items]
Principal amount		$ 71,748,000		65,958,000
Carrying value		$ 71,748,000		65,958,000
Mortgage and other notes payable, net | Loan 9 | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		3.00%
Mortgage and other notes payable, net | Net lease 1, periodic payment of principal and interest
Debt Instrument [Line Items]
Number of properties | property		2	2
Mortgage and other notes payable, net | Net lease 1, periodic payment of interest
Debt Instrument [Line Items]
Number of properties | property		1	1
Mortgage and other notes payable, net | Other notes payable
Debt Instrument [Line Items]
Number of optional extensions to initial maturity date | extension		3
Debt term extension available (in years)		1 year
Bank credit facility | Bank credit facility
Debt Instrument [Line Items]
Number of optional extensions to initial maturity date | extension		2
Debt term extension available (in years)		6 months
Credit facilities
Debt Instrument [Line Items]
Principal amount		$ 608,632,000		1,099,233,000
Carrying value		$ 608,632,000		1,099,233,000
Credit facilities | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		2.25%
Credit facilities | Bank credit facility
Debt Instrument [Line Items]
Principal amount		$ 0		113,500,000
Carrying value		0		113,500,000
Credit facilities | Master repurchase facilities
Debt Instrument [Line Items]
Capacity		2,250,000,000
Principal amount		583,400,000		780,211,000
Carrying value		$ 583,400,000		780,211,000
Percent of recourse of the financed amount		25.00%	25.00%
Credit facilities | Master repurchase facilities | LIBOR | Minimum
Debt Instrument [Line Items]
Interest rate margin (in percentage)		1.50%
Credit facilities | Master repurchase facilities | LIBOR | Maximum
Debt Instrument [Line Items]
Interest rate margin (in percentage)		2.60%
Credit facilities | CMBS credit facilities
Debt Instrument [Line Items]
Contractual interest rate		4.25%	4.25%
Principal amount		$ 25,232,000		205,522,000
Carrying value		$ 25,232,000		205,522,000
Credit facilities | CMBS credit facilities | Minimum
Debt Instrument [Line Items]
Initial debt term (in years)		1 month
Credit facilities | CMBS credit facilities | Maximum
Debt Instrument [Line Items]
Initial debt term (in years)		6 months
Credit facilities | Bank credit facility
Debt Instrument [Line Items]
Capacity		$ 450,000,000
Credit facilities | Bank credit facility | Bank credit facility
Debt Instrument [Line Items]
Principal amount		0		113,500,000
Carrying value		0		113,500,000
Credit facilities | Bank 1 facility 3 | Master repurchase facilities
Debt Instrument [Line Items]
Capacity		400,000,000
Principal amount		103,622,000		106,309,000
Carrying value		$ 103,622,000		106,309,000
Number of optional extensions to initial maturity date | extension		2
Debt term extension available (in years)		1 year
Credit facilities | Bank 1 facility 3 | Master repurchase facilities | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		1.91%
Credit facilities | Bank 2 facility 3 | Master repurchase facilities
Debt Instrument [Line Items]
Capacity		$ 200,000,000
Principal amount		21,353,000		22,750,000
Carrying value		$ 21,353,000		22,750,000
Number of optional extensions to initial maturity date | extension		2
Debt term extension available (in years)		1 year
Credit facilities | Bank 2 facility 3 | Master repurchase facilities | Subsequent event
Debt Instrument [Line Items]
Capacity	$ 21,400,000
Extension period	1 year
Credit facilities | Bank 2 facility 3 | Master repurchase facilities | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		2.50%
Credit facilities | Bank 3 facility 3 | Master repurchase facilities
Debt Instrument [Line Items]
Capacity		$ 600,000,000
Principal amount		202,952,000		265,633,000
Carrying value		$ 202,952,000		265,633,000
Credit facilities | Bank 3 facility 3 | Master repurchase facilities | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		2.14%
Credit facilities | Bank 7 facility 1 | Master repurchase facilities
Debt Instrument [Line Items]
Capacity		$ 500,000,000
Principal amount		124,704,000		221,421,000
Carrying value		$ 124,704,000		221,421,000
Debt term extension available (in years)		1 year
Credit facilities | Bank 7 facility 1 | Master repurchase facilities | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		2.01%
Credit facilities | Bank 8 facility 1 | Master repurchase facilities
Debt Instrument [Line Items]
Capacity		$ 250,000,000
Principal amount		130,769,000		164,098,000
Carrying value		$ 130,769,000		164,098,000
Debt term extension available (in years)		1 year
Credit facilities | Bank 8 facility 1 | Master repurchase facilities | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		1.98%
Credit facilities | Bank 9 Facility 1 | Master repurchase facilities
Debt Instrument [Line Items]
Capacity		$ 300,000,000
Principal amount		0		0
Carrying value		$ 0		0
Number of optional extensions to initial maturity date | extension		2
Debt term extension available (in years)		1 year
Credit facilities | Bank 9 Facility 1 | Master repurchase facilities | Minimum
Debt Instrument [Line Items]
Percent of recourse of the financed amount		25.00%	25.00%
Credit facilities | Bank 9 Facility 1 | Master repurchase facilities | Maximum
Debt Instrument [Line Items]
Percent of recourse of the financed amount		50.00%	50.00%
Credit facilities | Bank 1 facility 1 | CMBS credit facilities
Debt Instrument [Line Items]
Principal amount		$ 0		20,375,000
Carrying value		0		20,375,000
Credit facilities | Bank 1 facility 2 | CMBS credit facilities
Debt Instrument [Line Items]
Principal amount		0		18,834,000
Carrying value		0		18,834,000
Credit facilities | Bank 3 facility | CMBS credit facilities
Debt Instrument [Line Items]
Principal amount		0		0
Carrying value		0		0
Credit facilities | Bank 4 facility | CMBS credit facilities
Debt Instrument [Line Items]
Principal amount		0		0
Carrying value		0		0
Credit facilities | Bank 5 facility 1 | CMBS credit facilities
Debt Instrument [Line Items]
Principal amount		0		0
Carrying value		0		0
Credit facilities | Bank 5 facility 2 | CMBS credit facilities
Debt Instrument [Line Items]
Principal amount		0		0
Carrying value		$ 0		0
Credit facilities | Bank 6 facility 1 | CMBS credit facilities
Debt Instrument [Line Items]
Contractual interest rate		4.25%	4.25%
Principal amount		$ 13,165,000		83,584,000
Carrying value		$ 13,165,000		83,584,000
Credit facilities | Bank 6 facility 2 | CMBS credit facilities
Debt Instrument [Line Items]
Contractual interest rate		4.25%	4.25%
Principal amount		$ 12,067,000		82,729,000
Carrying value		12,067,000		82,729,000
CLNC 2019-FL1 | Securitization bonds payable, net | Investment grade notes
Debt Instrument [Line Items]
Principal amount		840,423,000		840,423,000
Carrying value		$ 834,621,000		$ 833,153,000
CLNC 2019-FL1 | Securitization bonds payable, net | Investment grade notes | LIBOR
Debt Instrument [Line Items]
Interest rate margin (in percentage)		1.59%