Summary of Significant Accounting Policies - Noncontrolling Interests (Details) $ / shares in Units, $ in Thousands				12 Months Ended
	Dec. 17, 2015 USD ($) shares	Mar. 01, 2015 USD ($)	Feb. 05, 2015 USD ($) $ / shares shares	Dec. 31, 2016 USD ($)	Dec. 31, 2016 USD ($) shares	Dec. 31, 2016 USD ($) Rate	Dec. 31, 2016 USD ($) properties	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) Rate	Apr. 01, 2016 USD ($)
Business Acquisition [Line Items]
Value of units issued for funding purchase price				$ 20,980	$ 20,980	$ 20,980	$ 20,980	$ 20,980	$ 0
Acquisition price				1,285,185					$ 840,958
Percentage of interest held						97.50%		43.00%	95.70%
Conversion ratio								1
Real estate taxes payable				5,571	$ 5,571	$ 5,571	$ 5,571	$ 5,571	$ 8,149
Equity investment		$ 5,000
Internal rate of return		15.00%
Reclassification from noncontrolling interests				8,500
Operating Partnership
Business Acquisition [Line Items]
Acquisition price				8,500
Units | Operating Partnership
Business Acquisition [Line Items]
Number of real estate properties acquired | properties							1
Number of units issued for funding purchase price (in shares) | shares					174,085
Value of units issued for funding purchase price				2,900	$ 2,900	$ 2,900	$ 2,900	$ 2,900
Number of shares | shares					217,549
Noncontrolling interest, decrease from redemptions or purchase of interests				$ 4,000
Series A Preferred units
Business Acquisition [Line Items]
Cumulative preferred return			5.00%
Shares issued upon conversion			1
Redemption value per share | $ / shares			$ 200
Period of time before redeemable			1 year
Minnetonka MOB
Business Acquisition [Line Items]
Number of units issued for funding purchase price (in shares) | shares			44,685
Acquisition price			$ 26,000
Value of Preferred Units			$ 9,700
Internal rate of return		15.00%
Minnetonka MOB | Units
Business Acquisition [Line Items]
Real estate taxes payable										$ 2,700
Business acquisition, equity interest redeemed, value assigned										$ 9,800
Minnetonka MOB | Series A Preferred units | Units | Operating Partnership
Business Acquisition [Line Items]
Number of units issued for funding purchase price (in shares) | shares			44,685
Nashville MOB
Business Acquisition [Line Items]
Acquisition price	$ 45,440
Value of Preferred Units	$ 19,700
Nashville MOB | Series A Preferred units | Units | Operating Partnership
Business Acquisition [Line Items]
Number of units issued for funding purchase price (in shares) | shares	91,236
Value of units issued for funding purchase price	$ 19,700