Commitments and Contingencies - Lease Commitments (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020 USD ($) property	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) property	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Lease Commitments
Properties subject to ground leases | property	23		23
Lease Cost
Fixed lease cost	$ 8,015	$ 7,937	$ 23,161	$ 23,045
Variable lease cost	3,130	4,183	10,217	12,513
Sublease income	(187)	(208)	(560)	(542)
Total operating lease cost	$ 10,958	$ 11,912	32,818	35,016
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from operating leases			$ 33,301	$ 36,268
Weighted-average remaining lease term - operating leases	34 years 7 months 6 days	35 years 9 months 18 days	34 years 7 months 6 days	35 years 9 months 18 days
Weighted-average discount rate - operating leases	4.86%	4.87%	4.86%	4.87%
Operating Lease Liabilities
2020	$ 32,706		$ 32,706
2021	32,697		32,697
2022	32,721		32,721
2023	32,863		32,863
2024	32,997		32,997
Thereafter	914,286		914,286
Future minimum gross lease payments	1,078,270		1,078,270
Impact of discounting	(560,816)		(560,816)
Operating lease liabilities	$ 517,454		$ 517,454		$ 516,809