Subsequent Events (Details)		3 Months Ended		6 Months Ended
	May 09, 2017 USD ($)	Jun. 30, 2017 USD ($) item	Mar. 31, 2017 USD ($) a item	Jun. 30, 2016 USD ($) item	Apr. 27, 2017 USD ($)
Subsequent Events
Number of acquisitions | item			11	7
Area of real estate property | a			150,781
Purchase price			$ 98,600,000	$ 237,900,000
Agreement termination payment amount			1,600,000
Agreement termination fee			$ 200,000
Subsequent event
Subsequent Events
Cash dividend declared	$ 0.1275
Subsequent event | Promissory Note
Subsequent Events
Principal amount of loan					$ 1,647,000
Subsequent event | Asset acquisition
Subsequent Events
Number of acquisitions | item		3
Total Consideration		$ 7,600,000