Real Estate and Lending Activities - Adeptus Health - Additional Information (Detail) $ in Millions								6 Months Ended	15 Months Ended
	Oct. 01, 2018 Facility	Jun. 08, 2018 Facility	Apr. 01, 2018 Property	Jan. 01, 2018 Property	Dec. 01, 2017 Facility	Apr. 04, 2017 Facility	Mar. 31, 2017 USD ($)	Jun. 30, 2018 USD ($) Property Facility	Jun. 30, 2018 USD ($) Property
Business Acquisition [Line Items]
Gain offset by non-cash charges | $							$ 0.6
Adeptus Health [Member]
Business Acquisition [Line Items]
Number of properties closed | Property			3	5
Amortization of straight line rent receivables | $								$ 3.9
Number of facilities transitioned | Facility								16
Percentage of investment in facilities on total assets								1.00%
Number of leased properties | Property								21
Leased properties | $								$ 131.3	$ 131.3
Number of properties re-tenanted | Property									22
Transitioned properties investment | $								172.1	$ 172.1
Adeptus Health [Member] | Ochsner [Member]
Business Acquisition [Line Items]
Gain offset by non-cash charges | $								$ 0.5
Adeptus Health [Member] | Total Gross Assets [Member] | Credit Concentration Risk [Member]
Business Acquisition [Line Items]
Percentage of Total Gross Assets								1.40%
Adeptus Health [Member] | Louisiana Freestanding Emergency Facilities [Member]
Business Acquisition [Line Items]
Number of facilities transferred | Facility						3
Adeptus Health [Member] | Colorado Freestanding Emergency Facilities [Member]
Business Acquisition [Line Items]
Number of facilities transferred | Facility					11
Adeptus Health [Member] | Arizona Freestanding Emergency Facilities [Member]
Business Acquisition [Line Items]
Number of facilities transferred | Facility		8
Adeptus Health [Member] | Scenario, Forecast [Member]
Business Acquisition [Line Items]
Number of facilities transitioned | Facility	7