Credit Concentration - Schedule of ABR (Annualized Base Rent) (Details) - Sales Revenue, Services, Net $ in Thousands	3 Months Ended
	Mar. 31, 2019 USD ($) Rate
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 286,689
Percent of ABR (annualized base rent) | Rate	100.00%
Customer Concentration Risk | CommonSpirit - CHI - Nebraska
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 16,390
Percent of ABR (annualized base rent)	5.70%
Customer Concentration Risk | CommonSpirit - CHI - KentuckyOne
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 13,579
Percent of ABR (annualized base rent)	4.70%
Customer Concentration Risk | Northside Hospital
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 10,098
Percent of ABR (annualized base rent)	3.50%
Customer Concentration Risk | Baylor Scott and White Health
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 7,770
Percent of ABR (annualized base rent)	2.70%
Customer Concentration Risk | Ascension - St. Vincent's - Indianapolis
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 7,384
Percent of ABR (annualized base rent)	2.60%
Customer Concentration Risk | Remaining portfolio
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 231,468
Percent of ABR (annualized base rent) | Rate	80.80%
Geographic Concentration Risk | Texas
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 44,804
Percent of ABR (annualized base rent)	15.60%
Geographic Concentration Risk | Georgia
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 25,040
Percent of ABR (annualized base rent)	8.70%
Geographic Concentration Risk | Indiana
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 19,805
Percent of ABR (annualized base rent)	6.90%
Geographic Concentration Risk | Nebraska
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 17,798
Percent of ABR (annualized base rent)	6.20%
Geographic Concentration Risk | Minnesota
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 17,175
Percent of ABR (annualized base rent)	6.00%
Geographic Concentration Risk | Other
Concentration Risk [Line Items]
Total ABR (annualized base rent)	$ 162,067
Percent of ABR (annualized base rent)	56.60%