Summary of Significant Accounting Policies - Noncontrolling Interests (Details) $ / shares in Units, $ in Thousands					3 Months Ended
	Mar. 01, 2018 USD ($)	Jan. 09, 2018 USD ($) shares	Mar. 01, 2015 USD ($)	Feb. 05, 2015 $ / shares	Mar. 31, 2018 USD ($) shares	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($)
Business Acquisition [Line Items]
Unit conversion ratio					1
Percentage of interest held					97.10%
Embedded derivative					$ 3,776		$ 0
Percentage of internal rate of return			15.00%
Net income (loss) attributable to redeemable noncontrolling interest						$ 100
Equity Method Investments			$ 5,000
HealthEast Clinic & Specialty Center
Business Acquisition [Line Items]
Number of units issued for funding purchase price (in shares) | shares		104,172			104,172
Consideration transferred, equity interests issued and issuable		$ 22,700
Redeemable Noncontrolling Interest Buyouts
Business Acquisition [Line Items]
Net income (loss) attributable to redeemable noncontrolling interest	$ 6,406
Series A Preferred Units
Business Acquisition [Line Items]
Cumulative preferred return				5.00%
Redeemable noncontrolling interest, equity, preferred, redemption shares in exchange				1
Redemption value (in dollars per share) | $ / shares				$ 200
Period in which preferred units will be redeemable				1 year