Investment in Unconsolidated Joint Venture (Condensed Balance Sheet) (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014	Oct. 30, 2013
Schedule of Equity Method Investments [Line Items]
Real estate assets, at cost	$ 1,897,792	$ 1,888,366
Less accumulated depreciation and amortization	(166,680)	(124,178)
Total real estate investments, net	1,731,112	1,764,188
Total assets	2,061,649	2,120,835
Total liabilities	920,359	925,158
Deficit	(309,669)	(255,478)
Total liabilities and equity	2,061,649	2,120,835
Company's basis	226,306	225,501
Worldwide Plaza
Schedule of Equity Method Investments [Line Items]
Real estate assets, at cost	713,339	704,143
Less accumulated depreciation and amortization	(107,075)	(97,181)
Total real estate investments, net	606,264	606,962
Other assets	269,005	255,784
Total assets	875,269	862,746
Debt	875,000	875,000	$ 875,000
Other liabilities	18,807	12,442
Total liabilities	893,807	887,442
Deficit	(18,538)	(24,696)
Total liabilities and equity	875,269	862,746
Company's basis	$ 226,306	$ 225,501