Rent Expense - Additional Information (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2019 USD ($) properties healthcareproperty	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)
Operating Leased Assets [Line Items]
Number of properties subject to parking lease | properties	3
Number of properties subject to air space lease | healthcareproperty	1
Number of properties subject to ground leases | properties	79
Number of office space leases | properties	10
Maximum lease terms	88 years
Operating lease, weighted average remaining lease term	44 years
Right-of-use lease assets, net	$ 125,775
Lease liabilities	$ 60,692		$ 0
Operating lease, weighted average discount rate, percent	4.30%
ASU 2016-02
Operating Leased Assets [Line Items]
Right-of-use lease assets, net		$ 126,700
Lease liabilities		$ 61,000