Derivative Instruments (Contract Details) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($)	Sep. 30, 2019 USD ($)	Sep. 30, 2020 EUR (€)	Sep. 30, 2020 USD ($)	Sep. 30, 2020 GBP (£)	Jun. 26, 2020 GBP (£) $ / €	May 27, 2020 GBP (£) $ / €	Mar. 10, 2020 EUR (€) $ / €	Mar. 02, 2020 EUR (€) $ / €	Feb. 21, 2020 GBP (£) $ / £	Dec. 09, 2019 GBP (£) $ / £	Oct. 24, 2019 GBP (£) $ / £
Not Designated as Hedging Instrument
Derivative [Line Items]
Gain (Loss) on Derivative Instruments | $	$ (867,000)	$ (97,000)	$ 7,602,000	$ (1,284,000)
Not Designated as Hedging Instrument | Interest Rate Cap
Derivative [Line Items]
Gain (Loss) on Derivative Instruments | $	(64,000)	(97,000)	(138,000)	(408,000)
Not Designated as Hedging Instrument | Interest Rate Swap
Derivative [Line Items]
Gain (Loss) on Derivative Instruments | $	68,000	0	416,000	0
Not Designated as Hedging Instrument | Foreign Exchange Forward
Derivative [Line Items]
Derivative, notional amount								£ 32,500,000		€ 50,000,000	€ 60,000,000		£ 15,000,000	£ 31,000,000
Traded Currency Rate								1.24		1.14	1.12		1.32	1.29
Gain (Loss) on Derivative Instruments | $	$ (871,000)	$ 0	$ 7,324,000	$ (876,000)
Not Designated as Hedging Instrument | Foreign Exchange Forward | Foreign exchange forward contract
Derivative [Line Items]
Derivative, notional amount									£ 31,000,000			£ 31,000,000
Traded Currency Rate									1.23			1.30
Not Designated as Hedging Instrument | Foreign Exchange Forward | Foreign exchange forward contract
Derivative [Line Items]
Derivative, notional amount									£ 15,000,000			£ 15,000,000
Traded Currency Rate									1.23			1.30
Secured Debt | Libor
Derivative [Line Items]
Aggregate principal							£ 55,100,000
Montrose Student Residences | Secured Debt | Euribor
Derivative [Line Items]
Aggregate principal | €					€ 22,605,000
Montrose Student Residences | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Cap | Euribor
Derivative [Line Items]
Derivative, notional amount | €					€ 16,954,000
Derivative, description of variable rate basis			Euribor
Derivative, cap interest rate (percent)					1.25%	1.25%	1.25%
Queen's Court Student Residences | Secured Debt | Libor
Derivative [Line Items]
Aggregate principal							£ 29,500,000
Queen's Court Student Residences | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Cap | Libor
Derivative [Line Items]
Derivative, notional amount							£ 22,125,000
Derivative, description of variable rate basis			LIBOR
Derivative, cap interest rate (percent)					2.00%	2.00%	2.00%
Venue Museum District | Secured Debt | Libor
Derivative [Line Items]
Aggregate principal | $						$ 45,000,000
Venue Museum District | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Cap | Libor
Derivative [Line Items]
Derivative, notional amount | $						$ 45,000,000
Derivative, description of variable rate basis			LIBOR
Derivative, cap interest rate (percent)					3.50%	3.50%	3.50%
Fresh Park Venlo | Secured Debt | Euribor
Derivative [Line Items]
Aggregate principal | €					€ 75,000,000
Fresh Park Venlo | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Cap | Euribor
Derivative [Line Items]
Derivative, notional amount | €					€ 52,487,000
Derivative, description of variable rate basis			Euribor
Derivative, cap interest rate (percent)					2.00%	2.00%	2.00%
Maintal Logistics | Secured Debt | Euribor
Derivative [Line Items]
Aggregate principal | €					€ 23,500,000
Maintal Logistics | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Cap | Euribor
Derivative [Line Items]
Derivative, notional amount | €					€ 16,450,000
Derivative, description of variable rate basis			Euribor
Derivative, cap interest rate (percent)					2.00%	2.00%	2.00%
ABC Westland | Secured Debt | Euribor
Derivative [Line Items]
Aggregate principal | €					€ 75,000,000
ABC Westland | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Cap | Euribor
Derivative [Line Items]
Derivative, notional amount | €					€ 52,500,000
Derivative, description of variable rate basis			Euribor
Derivative, cap interest rate (percent)					1.00%	1.00%	1.00%
Łódź Urban Logistics | Secured Debt
Derivative [Line Items]
Aggregate principal | €					€ 13,600,000
Łódź Urban Logistics | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Swap | Euribor
Derivative [Line Items]
Derivative, notional amount | €					€ 13,600,000
Derivative, description of variable rate basis			Euribor
Derivative, swap pay rate/strike rate (percent)					(0.36%)	(0.36%)	(0.36%)
Gdańsk PL II | Secured Debt
Derivative [Line Items]
Aggregate principal | €					€ 16,800,000
Gdańsk PL II | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Swap | Euribor
Derivative [Line Items]
Derivative, notional amount | €					€ 16,800,000
Derivative, description of variable rate basis			Euribor
Derivative, swap pay rate/strike rate (percent)					(0.36%)	(0.36%)	(0.36%)
Glasgow West End | Secured Debt | Libor
Derivative [Line Items]
Aggregate principal							£ 43,200,000
Glasgow West End | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Cap | Libor
Derivative [Line Items]
Derivative, notional amount							£ 32,400,000
Derivative, description of variable rate basis			LIBOR
Derivative, cap interest rate (percent)					2.00%	2.00%	2.00%
Charles Tyrwhitt | Secured Debt | Libor
Derivative [Line Items]
Aggregate principal							£ 9,598,000
Charles Tyrwhitt | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Cap | Libor
Derivative [Line Items]
Derivative, notional amount							£ 9,598,000
Derivative, description of variable rate basis			LIBOR
Derivative, cap interest rate (percent)					1.50%	1.50%	1.50%
DSG Bristol | Secured Debt | Libor
Derivative [Line Items]
Aggregate principal							£ 20,240,000
DSG Bristol | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Cap | Libor
Derivative [Line Items]
Derivative, notional amount							£ 20,240,000
Derivative, description of variable rate basis			LIBOR
Derivative, cap interest rate (percent)					1.50%	1.50%	1.50%
Royal Mail | Secured Debt | Libor
Derivative [Line Items]
Aggregate principal							£ 13,970,000
Royal Mail | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Cap | Libor
Derivative [Line Items]
Derivative, notional amount							£ 13,970,000
Derivative, description of variable rate basis			LIBOR
Derivative, cap interest rate (percent)					1.50%	1.50%	1.50%
Wakefield Logistics | Secured Debt | Libor
Derivative [Line Items]
Aggregate principal							£ 11,330,000
Wakefield Logistics | Secured Debt | Not Designated as Hedging Instrument | Interest Rate Cap | Libor
Derivative [Line Items]
Derivative, notional amount							£ 11,330,000
Derivative, description of variable rate basis			LIBOR
Derivative, cap interest rate (percent)					1.50%	1.50%	1.50%