Prepaid Expenses and Other Current Assets and Other Assets (Schedule of Prepaid Expense and Other Current Assets) (Details) - USD ($) $ in Thousands		Jun. 30, 2019	Dec. 31, 2018
Prepaid Expenses and Other Current Assets and Other Assets [Abstract]
Prepaid ground rent		$ 1,409	$ 34,276
Loan receivables			11,178
Marketable Securities		25,537	239
Other		21,306	17,433
Total prepaid expenses and other current assets	[1]	$ 48,252	$ 63,126

[1] On January 1, 2019, the Company adopted ASU 2016-02 which requires lessees to recognize a right-of-use asset and a lease liability. Upon adoption, certain assets and liabilities were reclassified to Right-of-use assets, net and lease liabilities in accordance with provisions of ASU 2016-02. See Note 1 for further discussion.