Risk Management and Use of Derivative Financial Instruments - Derivative Gain Loss Recognized in OCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Derivative Instruments, Gain (Loss)
Amount of gain (loss) recognized on derivatives in other comprehensive income (loss)	$ (9,397)	$ (2,413)	$ 3,900	$ 480
Derivatives in Cash Flow Hedging Relationships | Foreign currency collars
Derivative Instruments, Gain (Loss)
Amount of gain (loss) recognized on derivatives in other comprehensive income (loss)	(6,311)	262	11,505	3,878
Derivatives in Cash Flow Hedging Relationships | Foreign currency forward contracts
Derivative Instruments, Gain (Loss)
Amount of gain (loss) recognized on derivatives in other comprehensive income (loss)	(2,943)	(2,289)	(5,272)	(1,170)
Derivatives in Cash Flow Hedging Relationships | Interest rate swaps
Derivative Instruments, Gain (Loss)
Amount of gain (loss) recognized on derivatives in other comprehensive income (loss)	(122)	(562)	(2,359)	(2,377)
Derivatives in Cash Flow Hedging Relationships | Interest rate caps
Derivative Instruments, Gain (Loss)
Amount of gain (loss) recognized on derivatives in other comprehensive income (loss)	(1)	176	1	149
Derivatives in Net Investment Hedging Relationships | Foreign currency collars
Derivative Instruments, Gain (Loss)
Amount of gain (loss) recognized on derivatives in other comprehensive income (loss)	(20)	1	25	1
Derivatives in Net Investment Hedging Relationships | Foreign currency forward contracts
Derivative Instruments, Gain (Loss)
Amount of gain (loss) recognized on derivatives in other comprehensive income (loss)	$ 0	$ (1)	$ 0	$ (1)