Investments in Unconsolidated Joint Ventures - Summary of Financial Information (Details) - 712 Fifth Avenue [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Schedule Of Equity Method Investments [Line Items]
Rental property, net	$ 198,722		$ 198,722		$ 221,827
Other assets	56,156		56,156		46,126
Total assets	254,878		254,878		267,953
Mortgage and notes payable	246,500		246,500		246,500
Other liabilities	15,260		15,260		30,321
Total liabilities	261,760		261,760		276,821
Equity	(6,882)		(6,882)		(8,868)
Total liabilities and equity	254,878		254,878		$ 267,953
Rental income	12,392		24,446
Tenant reimbursement income	1,375		2,736
Fee and other income	344		623
Total revenue	14,111		27,805
Operating	5,831		12,057
Depreciation and amortization	2,954		5,884
Total expenses	8,785		17,941
Operating income	5,326		9,864
Unrealized gain on interest rate swaps	1,248		2,020
Interest and other income, net	4		5
Interest and debt expense	(2,611)		(6,039)
Net income	$ 3,967		$ 5,850
Predecessor [Member]
Schedule Of Equity Method Investments [Line Items]
Rental income		$ 11,457		$ 22,689
Tenant reimbursement income		1,124		2,269
Fee and other income		283		638
Total revenue		12,864		25,596
Operating		5,565		11,326
Depreciation and amortization		2,786		5,525
General and administrative		25		55
Total expenses		8,376		16,906
Operating income		4,488		8,690
Unrealized gain on interest rate swaps		1,058		2,645
Interest and debt expense		(3,677)		(7,286)
Net income		$ 1,869		$ 4,049