Fair Value Measurements - Fair Value of Company's Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Assets:
Notes receivable, net	$ 24,102	$ 22,694
Liabilities:
Credit facility	(340,818)	(583,323)
Notes payable	(968,432)	(967,789)
Mortgage debt	(58,375)	(83,341)
Carrying Amount
Assets:
Real estate loans receivable, net	164,184	178,240
Notes receivable, net	24,102	22,694
Liabilities:
Credit facility	(345,000)	(589,000)
Notes payable	(975,000)	(975,000)
Mortgage debt	(58,592)	(83,613)
Carrying Amount | Derivative assets
Assets:
Derivative assets	0	4,933
Liabilities:
Derivative liabilities	(5,750)
Carrying Amount | Derivative liabilities
Liabilities:
Derivative liabilities	(10,895)	(4,290)
Fair Value
Assets:
Real estate loans receivable, net	166,496	178,095
Notes receivable, net	24,102	22,694
Liabilities:
Credit facility	(345,000)	(589,000)
Notes payable	(1,026,641)	(1,003,385)
Mortgage debt	(60,644)	(85,110)
Fair Value | Derivative assets
Assets:
Derivative assets	0	4,933
Fair Value | Derivative liabilities
Liabilities:
Derivative liabilities	$ (10,895)	$ (4,290)