Schedule III - Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2015
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances				$ 2,941,524
Initial cost to company, Land				2,042,071
Initial cost to company, Building and Improvements				5,442,199
Costs capitalized subsequent to acquisition, Building and Improvements				167,847
Gross amount at which carried at close of period, Land				2,042,071
Gross amount at which carried at close of period, Buildings and Improvements				5,610,046
Gross amount at which carried at close of period, Total	$ 7,652,117	$ 7,530,239	$ 414,998	7,652,117
Accumulated depreciation and amortization	(243,089)	(81,050)	(57,689)	(243,089)
Costs capitalized subsequent to acquisition, Building and Improvements, other				(1,627)
Gross amount at which carried at close of period, Buildings and Improvements, other				(1,627)
Gross amount at which carried at close of period, other				(1,627)
Accumulated depreciation and amortization, other	$ (36)
Date acquired, other	Nov. 24, 2014
Rental Property
Balance at beginning of period	$ 7,530,239	414,998	414,855
Acquisitions		64,650
Acquisition of properties in connection with the Formation Transactions		7,043,650
Buildings and improvements	123,277	9,676	147
Assets sold and written-off	(1,399)	(2,735)	(4)
Balance at end of period	7,652,117	7,530,239	414,998
Accumulated Depreciation
Balance at beginning of period	81,050	57,689	48,425
Additions charged to expense	163,438	26,096	9,268
Accumulated depreciation on assets sold and written-off	(1,399)	(2,735)	(4)
Balance at end of period	$ 243,089	$ 81,050	$ 57,689
Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed, other	5 years
Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed, other	40 years
1633 Broadway [Member]
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances				1,013,544
Initial cost to company, Land				502,846
Initial cost to company, Building and Improvements				1,398,341
Costs capitalized subsequent to acquisition, Building and Improvements				38,530
Gross amount at which carried at close of period, Land				502,846
Gross amount at which carried at close of period, Buildings and Improvements				1,436,871
Gross amount at which carried at close of period, Total	$ 1,939,717			1,939,717
Accumulated depreciation and amortization	$ (43,602)			(43,602)
Date of construction	Dec. 31, 1971
Date acquired	Nov. 24, 2014
Rental Property
Balance at end of period	$ 1,939,717
Accumulated Depreciation
Balance at end of period	$ 43,602
1633 Broadway [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
1633 Broadway [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years
1301 Avenue of the Americas [Member]
Real Estate And Accumulated Depreciation [Line Items]
Initial cost to company, Land				406,039
Initial cost to company, Building and Improvements				1,051,697
Costs capitalized subsequent to acquisition, Building and Improvements				15,433
Gross amount at which carried at close of period, Land				406,039
Gross amount at which carried at close of period, Buildings and Improvements				1,067,130
Gross amount at which carried at close of period, Total	$ 1,473,169			1,473,169
Accumulated depreciation and amortization	$ (33,761)			(33,761)
Date of construction	Dec. 31, 1963
Date acquired	Nov. 24, 2014
Rental Property
Balance at end of period	$ 1,473,169
Accumulated Depreciation
Balance at end of period	$ 33,761
1301 Avenue of the Americas [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
1301 Avenue of the Americas [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years
31 West 52nd Street [Member]
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances				413,490
Initial cost to company, Land				221,318
Initial cost to company, Building and Improvements				604,994
Costs capitalized subsequent to acquisition, Building and Improvements				3,468
Gross amount at which carried at close of period, Land				221,318
Gross amount at which carried at close of period, Buildings and Improvements				608,462
Gross amount at which carried at close of period, Total	$ 829,780			829,780
Accumulated depreciation and amortization	$ (19,464)			(19,464)
Date of construction	Dec. 31, 1987
Date acquired	Nov. 24, 2014
Rental Property
Balance at end of period	$ 829,780
Accumulated Depreciation
Balance at end of period	$ 19,464
31 West 52nd Street [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
31 West 52nd Street [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years
1325 Avenue of the Americas [Member]
Real Estate And Accumulated Depreciation [Line Items]
Initial cost to company, Land				174,688
Initial cost to company, Building and Improvements				370,553
Costs capitalized subsequent to acquisition, Building and Improvements				9,464
Gross amount at which carried at close of period, Land				174,688
Gross amount at which carried at close of period, Buildings and Improvements				380,017
Gross amount at which carried at close of period, Total	$ 554,705			554,705
Accumulated depreciation and amortization	$ (12,820)			(12,820)
Date of construction	Dec. 31, 1989
Date acquired	Nov. 24, 2014
Rental Property
Balance at end of period	$ 554,705
Accumulated Depreciation
Balance at end of period	$ 12,820
1325 Avenue of the Americas [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
1325 Avenue of the Americas [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years
900 Third Avenue [Member]
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances				274,337
Initial cost to company, Land				103,741
Initial cost to company, Building and Improvements				296,031
Costs capitalized subsequent to acquisition, Building and Improvements				3,117
Gross amount at which carried at close of period, Land				103,741
Gross amount at which carried at close of period, Buildings and Improvements				299,148
Gross amount at which carried at close of period, Total	$ 402,889			402,889
Accumulated depreciation and amortization	$ (10,791)			(10,791)
Date of construction	Dec. 31, 1983
Date acquired	Nov. 24, 2014
Rental Property
Balance at end of period	$ 402,889
Accumulated Depreciation
Balance at end of period	$ 10,791
900 Third Avenue [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
900 Third Avenue [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years
Total New York
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances				1,701,371
Initial cost to company, Land				1,408,632
Initial cost to company, Building and Improvements				3,721,616
Costs capitalized subsequent to acquisition, Building and Improvements				70,012
Gross amount at which carried at close of period, Land				1,408,632
Gross amount at which carried at close of period, Buildings and Improvements				3,791,628
Gross amount at which carried at close of period, Total	$ 5,200,260			5,200,260
Accumulated depreciation and amortization	(120,438)			(120,438)
Rental Property
Balance at end of period	5,200,260
Accumulated Depreciation
Balance at end of period	120,438
425 Eye Street [Member]
Real Estate And Accumulated Depreciation [Line Items]
Initial cost to company, Land				93,669
Initial cost to company, Building and Improvements				98,088
Costs capitalized subsequent to acquisition, Building and Improvements				2,316
Gross amount at which carried at close of period, Land				93,669
Gross amount at which carried at close of period, Buildings and Improvements				100,404
Gross amount at which carried at close of period, Total	194,073			194,073
Accumulated depreciation and amortization	$ (73,284)			(73,284)
Date of construction	Dec. 31, 1973
Date acquired	Nov. 24, 2014
Rental Property
Balance at end of period	$ 194,073
Accumulated Depreciation
Balance at end of period	$ 73,284
425 Eye Street [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
425 Eye Street [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years
Liberty Place [Member]
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances				84,000
Initial cost to company, Land				46,401
Initial cost to company, Building and Improvements				96,422
Costs capitalized subsequent to acquisition, Building and Improvements				9,571
Gross amount at which carried at close of period, Land				46,401
Gross amount at which carried at close of period, Buildings and Improvements				105,993
Gross amount at which carried at close of period, Total	$ 152,394			152,394
Accumulated depreciation and amortization	$ (4,025)			(4,025)
Date of construction	Dec. 31, 1993
Date acquired	Nov. 24, 2014
Rental Property
Balance at end of period	$ 152,394
Accumulated Depreciation
Balance at end of period	$ 4,025
Liberty Place [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
Liberty Place [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years
1899 Pennsylvania Avenue [Member]
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances				89,116
Initial cost to company, Land				52,568
Initial cost to company, Building and Improvements				94,874
Costs capitalized subsequent to acquisition, Building and Improvements				3,577
Gross amount at which carried at close of period, Land				52,568
Gross amount at which carried at close of period, Buildings and Improvements				98,451
Gross amount at which carried at close of period, Total	$ 151,019			151,019
Accumulated depreciation and amortization	$ (3,318)			(3,318)
Date of construction	Dec. 31, 1915
Date acquired	Nov. 24, 2014
Rental Property
Balance at end of period	$ 151,019
Accumulated Depreciation
Balance at end of period	$ 3,318
1899 Pennsylvania Avenue [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
1899 Pennsylvania Avenue [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years
2099 Pennsylvania Avenue [Member]
Real Estate And Accumulated Depreciation [Line Items]
Initial cost to company, Land				50,631
Initial cost to company, Building and Improvements				103,992
Costs capitalized subsequent to acquisition, Building and Improvements				9,994
Gross amount at which carried at close of period, Land				50,631
Gross amount at which carried at close of period, Buildings and Improvements				113,986
Gross amount at which carried at close of period, Total	$ 164,617			164,617
Accumulated depreciation and amortization	$ (3,054)			(3,054)
Date of construction	Dec. 31, 2001
Date acquired	Nov. 24, 2014
Rental Property
Balance at end of period	$ 164,617
Accumulated Depreciation
Balance at end of period	$ 3,054
2099 Pennsylvania Avenue [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
2099 Pennsylvania Avenue [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years
Waterview [Member]
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances				210,000
Initial cost to company, Land				78,300
Initial cost to company, Building and Improvements				297,669
Costs capitalized subsequent to acquisition, Building and Improvements				36,412
Gross amount at which carried at close of period, Land				78,300
Gross amount at which carried at close of period, Buildings and Improvements				334,081
Gross amount at which carried at close of period, Total	$ 412,381			412,381
Accumulated depreciation and amortization	$ (3,579)			(3,579)
Date of construction	Dec. 31, 2007
Date acquired	May 31, 2007
Rental Property
Balance at end of period	$ 412,381
Accumulated Depreciation
Balance at end of period	$ 3,579
Waterview [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
Waterview [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years
Total Washington, D.C.
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances				383,116
Initial cost to company, Land				321,569
Initial cost to company, Building and Improvements				691,045
Costs capitalized subsequent to acquisition, Building and Improvements				61,870
Gross amount at which carried at close of period, Land				321,569
Gross amount at which carried at close of period, Buildings and Improvements				752,915
Gross amount at which carried at close of period, Total	$ 1,074,484			1,074,484
Accumulated depreciation and amortization	(87,260)			(87,260)
Rental Property
Balance at end of period	1,074,484
Accumulated Depreciation
Balance at end of period	87,260
One Market Plaza [Member]
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances				857,037
Initial cost to company, Land				288,744
Initial cost to company, Building and Improvements				988,014
Costs capitalized subsequent to acquisition, Building and Improvements				33,095
Gross amount at which carried at close of period, Land				288,744
Gross amount at which carried at close of period, Buildings and Improvements				1,021,109
Gross amount at which carried at close of period, Total	1,309,853			1,309,853
Accumulated depreciation and amortization	$ (33,494)			(33,494)
Date of construction	Dec. 31, 1976
Date acquired	Nov. 24, 2014
Rental Property
Balance at end of period	$ 1,309,853
Accumulated Depreciation
Balance at end of period	$ 33,494
One Market Plaza [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
One Market Plaza [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years
Total California
Real Estate And Accumulated Depreciation [Line Items]
Encumbrances				857,037
Initial cost to company, Land				288,744
Initial cost to company, Building and Improvements				988,014
Costs capitalized subsequent to acquisition, Building and Improvements				33,095
Gross amount at which carried at close of period, Land				288,744
Gross amount at which carried at close of period, Buildings and Improvements				1,021,109
Gross amount at which carried at close of period, Total	$ 1,309,853			1,309,853
Accumulated depreciation and amortization	(33,494)			(33,494)
Rental Property
Balance at end of period	1,309,853
Accumulated Depreciation
Balance at end of period	33,494
Residential Development Fund ("75 Howard") [Member]
Real Estate And Accumulated Depreciation [Line Items]
Initial cost to company, Land				23,126
Initial cost to company, Building and Improvements				41,524
Costs capitalized subsequent to acquisition, Building and Improvements				4,497
Gross amount at which carried at close of period, Land				23,126
Gross amount at which carried at close of period, Buildings and Improvements				46,021
Gross amount at which carried at close of period, Total	69,147			69,147
Accumulated depreciation and amortization	$ (1,861)			$ (1,861)
Date acquired	Mar. 31, 2014
Rental Property
Balance at end of period	$ 69,147
Accumulated Depreciation
Balance at end of period	$ 1,861
Residential Development Fund ("75 Howard") [Member] | Minimum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	5 years
Residential Development Fund ("75 Howard") [Member] | Maximum
Real Estate And Accumulated Depreciation [Line Items]
Life on which depreciation in latest income statement is computed	40 years