Basis of Presentation and Significant Accounting Policies (Recently Issued Accounting Literature) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2019 USD ($)	Jan. 01, 2019 USD ($) ground_lease
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of properties subject to ground leases | ground_lease				12
Right-of-use assets	$ 0		$ 379,546
Lease liabilities	0		$ 498,254
Accounting Standards Update 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right-of-use assets				$ 526,866
Lease liabilities				$ 526,866
Capitalized leasing costs	$ 5,538	$ 5,243