Subsequent Events (Details) $ / shares in Units, $ in Thousands							1 Months Ended	3 Months Ended			9 Months Ended
	Nov. 02, 2015 USD ($)	Oct. 30, 2015 USD ($)	Oct. 19, 2015 USD ($) $ / shares shares	Oct. 16, 2015 USD ($)	Oct. 13, 2015 USD ($) ft²	Jan. 21, 2015 $ / shares shares	Nov. 02, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jul. 31, 2015 ft²	Mar. 26, 2015 ft²
Subsequent events
Common shares sold | shares						18,975,000
Common share price (in dollars per share) | $ / shares						$ 16.40
Purchase price											$ 297,131
Shares issued upon exercise of the underwriters' overallotment option | shares						2,475,000
Number of partnership units issued | shares						18,975,000
Operating Partnership
Subsequent events
Purchase price								$ 11,200	$ 11,300	$ 10,000
Medical Building
Subsequent events
Area of property (in square feet) | ft²												26,783	20,329
Subsequent events
Subsequent events
Common shares sold | shares			15,812,500
Common share price (in dollars per share) | $ / shares			$ 15.00
Shares issued upon exercise of the underwriters' overallotment option | shares			2,062,500
Proceeds from Issuance of Common Stock			$ 226,300
Number of partnership units issued | shares			15,812,500
Subsequent events | Operating Partnership
Subsequent events
Purchase price							$ 53,455
Subsequent events | Medical office building condominium unit | Operating Partnership | AL & FL
Subsequent events
Purchase price					$ 23,805
Area of property (in square feet) | ft²					240,000
Subsequent events | Medical Building | Operating Partnership | Kansas City, MO
Subsequent events
Purchase price				$ 4,500
Subsequent events | Medical Building | Operating Partnership | Johnstown, CO
Subsequent events
Purchase price			$ 9,100
Subsequent events | Medical Building | Operating Partnership | Waldorf, MD
Subsequent events
Purchase price		$ 11,550
Subsequent events | Medical Building | Operating Partnership | Great Falls, MT
Subsequent events
Purchase price	$ 4,500
Amount of agreement to acquire a building	$ 26,300