Investments in Real Estate - Investments in Existing Properties (Details) - USD ($)	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Investments in Real Estate
Capitalized costs on existing properties	$ 6,800,000	$ 3,700,000
Re-leasing costs	759,000	277,000
Recurring capital expenditures	365,000	246,000
Nonrecurring capital expenditures	$ 5,700,000	$ 3,200,000