Investments in Real Estate - Investments in Existing Properties (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Investments in real estate properties
Capitalized costs on existing portfolio	$ 4,710	$ 11,767
Investments in existing properties
Investments in real estate properties
Capitalized costs on existing portfolio	4,400	6,100
Re-leasing costs	1,100	1,000
Recurring capital expenditures	23	172
Nonrecurring building improvements	$ 3,300	$ 4,900