Rent Expense - Additional Information (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) properties healthcareproperty	Mar. 31, 2016 USD ($)
Leases [Abstract]
Number of properties subject to parking lease	3
Number of properties subject to air space lease | healthcareproperty	1
Number of properties subject to ground leases	59
Number of office space leases	4
Maximum lease terms	99 years
Rent expenses for parking, air, and ground leases | $	$ 0.6	$ 0.4