Summary of Significant Accounting Policies (Details) $ in Thousands	Mar. 31, 2019 USD ($) joint_venture	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)
Summary of Significant Accounting Policies
Operating Lease, Right-of-Use Asset	$ 149,492	$ 150,803	$ 0
Real Estate Interests, Number of Joint Ventures | joint_venture	2
Noncontrolling Interest
Equity Method Investment, Ownership Percentage	50.00%
Intangible Assets, Net (Excluding Goodwill)	$ (5,143)	(5,676)	(52,448)
Accounts payable and other liabilities	(169,398)	(183,129)	(203,833)
Operating Lease, Liability	124,146	124,735	0
Accounting Standards Update 2016-02 [Member]
Summary of Significant Accounting Policies
Operating Lease, Right-of-Use Asset		150,803
Noncontrolling Interest
Intangible Assets, Net (Excluding Goodwill)		(46,772)
Accounts payable and other liabilities		(20,704)
Operating Lease, Liability		$ 124,735
Accounting Standards Update 2015-03 | Prepaid expenses and other assets
Summary of Significant Accounting Policies
Deferred financing costs	$ 1,200		$ 1,500