Leases - Summary of Quantitative Disclosures for Lessees (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)
Lease cost:
Total lease cost	$ 7,858	$ 15,494
Corporate Office Leases [Member]
Lease cost:
Operating lease cost	900	1,818
Short-term lease cost	56	112
Variable lease cost	$ 508	769
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from Operating leases		2,776
ROU assets obtained in exchange for new operating lease liabilities		$ 16,687
Weighted-average remaining lease term – operating leases	6 years 4 months 24 days	6 years 4 months 24 days
Weighted-average discount rate – operating leases	3.70%	3.70%
Ground Leases [Member]
Lease cost:
Operating lease cost	$ 5,550	$ 11,100
Variable lease cost	$ 844	1,695
Cash paid for amounts included in the measurement of lease liabilities:
Operating cash flows from Operating leases		8,635
ROU assets obtained in exchange for new operating lease liabilities		$ 422,018
Weighted-average remaining lease term – operating leases	56 years 7 months 6 days	56 years 7 months 6 days
Weighted-average discount rate – operating leases	5.00%	5.00%