Summary of Significant Accounting Policies (Narrative) (Details)	2 Months Ended	12 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($) segment property	Dec. 31, 2014 USD ($) property	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)
Equity, Class of Treasury Stock [Line Items]
Number of properties held-for-sale | property		3	0
Accretion of below- and amortization of above-market lease liabilities and assets, net		$ 7,918,000	$ 9,289,000	$ 2,626,000
Money market funds		200,000	300,000
Impairment charge			0	0
Cash and cash equivalents	$ 233,377,000	98,604,000	22,512,000	233,377,000	$ 5,354,000
Cash in excess of FDIC limit		96,300,000	18,900,000
Contingent rental revenue		600,000	0	0
Valuation allowance		3,100,000	1,700,000
Deferred tax assets		$ 3,100,000	1,700,000
Estimated tax rate		43.00%
Number of reportable segments | segment		1
2014 Advisor Multi-Year Outperformance Agreement
Equity, Class of Treasury Stock [Line Items]
Requisite service period		5 years
State and Local Jurisdiction
Equity, Class of Treasury Stock [Line Items]
Operating loss carryforwards		$ 3,000,000
Domestic Tax Authority
Equity, Class of Treasury Stock [Line Items]
Operating loss carryforwards		6,700,000
Depreciation and Amortization | In-Place Leases and Other Intangibles
Equity, Class of Treasury Stock [Line Items]
Amortization of intangibles		19,800,000	21,100,000	8,100,000
Property Operating Expense | Above Market Ground Lease
Equity, Class of Treasury Stock [Line Items]
Amortization of intangibles		$ 400,000	400,000	100,000
Building
Equity, Class of Treasury Stock [Line Items]
Fixtures useful life		40 years
Land Improvements
Equity, Class of Treasury Stock [Line Items]
Fixtures useful life		15 years
Furniture and Fixtures | Minimum
Equity, Class of Treasury Stock [Line Items]
Fixtures useful life		5 years
Furniture and Fixtures | Maximum
Equity, Class of Treasury Stock [Line Items]
Fixtures useful life		7 years
Worldwide Plaza
Equity, Class of Treasury Stock [Line Items]
Amortization of difference in basis	$ 2,161,000	$ 12,327,000	12,221,000	$ 2,200,000
Cash and cash equivalents		9,036,000	$ 3,784,000
Held-for-sale Property | Duane Reade
Equity, Class of Treasury Stock [Line Items]
Impairment charge		$ 900,000