Investment in Unconsolidated Joint Ventures - Balance Sheet of Unconsolidated Joint Ventures (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Real estate, net	$ 3,023,249	$ 3,024,271
Receivables and other assets	1,033	1,228
Total assets	3,619,235	3,704,714
Mortgage debt	1,238,336	1,339,450
Other liabilities	193,685	202,413
Total liabilities and equity	3,619,235	3,704,714
Equity Method Investee | US Airways Building
Schedule of Equity Method Investments [Line Items]
Cash	138	146
Restricted cash		0
Real estate, net	46,087	47,632
Intangible assets, net	2,265	5,078
Receivables and other assets	3,472	824
Total assets	51,962	53,680
Mortgage debt	13,105	13,441
Other liabilities	381	370
Partners' equity	38,476	39,869
Total liabilities and equity	51,962	53,680
Equity Method Investee | 7000 Central Park
Schedule of Equity Method Investments [Line Items]
Cash	421	1,218
Restricted cash		269
Real estate, net	0	48,532
Intangible assets, net	0	4,157
Receivables and other assets	41	2,099
Total assets	462	56,275
Mortgage debt	0	30,000
Other liabilities	85	1,561
Partners' equity	377	24,714
Total liabilities and equity	$ 462	$ 56,275