Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2015

Accounting Policies [Abstract]

Schedule of estimated useful lives

Properties are depreciated using the straight-line method over the estimated useful lives of the assets. The estimated useful lives are as follows:

Category	Term
Building (fee ownership)	40 years
Building improvements	shorter of remaining life of the building or useful life
Building (leasehold interest)	lesser of 40 years or remaining term of the lease
Property under capital lease	remaining lease term
Furniture and fixtures	four to seven years
Tenant improvements	shorter of remaining term of the lease or useful life

Summary of identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases)

The following summarizes our identified intangible assets (acquired above-market leases and in-place leases) and intangible liabilities (acquired below-market leases) as of December 31, 2015 and 2014 (in thousands):

	December 31,
	2015			2014
Identified intangible assets (included in other assets):
Gross amount	$	939,518		$	664,297
Accumulated amortization	(403,747		)	(383,236		)
Net(1)	$	535,771		$	281,061
Identified intangible liabilities (included in deferred revenue):
Gross amount	$	866,561		$	655,755
Accumulated amortization	(486,928		)	(483,948		)
Net(1)	$	379,633		$	171,807

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(1) As of December 31, 2015, $0.2 million and $0.1 million of net intangible assets and net intangible liabilities, respectively, were reclassified to assets held for sale and liabilities related to assets held for sale.

Schedule of estimated annual amortization of acquired above-market leases, net of acquired below-market leases

The estimated annual amortization of acquired above-market leases, net of acquired (below-market) leases (a component of rental revenue), for each of the five succeeding years is as follows (in thousands):

2016	$	4,002
2017	2,129
2018	439
2019	(376		)
2020	(595		)

Schedule of estimated annual amortization of all other identifiable assets

The estimated annual amortization of all other identifiable assets (a component of depreciation and amortization expense) including tenant improvements for each of the five succeeding years is as follows (in thousands):

2016	$	9,931
2017	8,507
2018	7,207
2019	6,706
2020	6,453

Schedule of marketable securities

At December 31, 2015 and 2014, we held the following marketable securities (in thousands):

	December 31,
	2015		2014
Equity marketable securities	$	4,704	$	4,332
Mortgage-backed securities	40,434		35,097
Total marketable securities available-for-sale	$	45,138	$	39,429

Schedule of Restated Balance Sheets

The accompanying consolidated balance sheet of the Company as of December 31, 2014 and the related statements of equity for the years ended December 31, 2014, 2013, and 2012 have been revised to correct the misclassification as follows (in thousands):

		As Previously Reported			As Adjusted
Consolidated balance sheet and consolidated statement of equity as of December 31, 2014:
	Common shares	$	1,010		$	974
	Additional paid-in capital	5,289,479			5,113,759
	Treasury shares	(320,471		)	—
	Retained earnings	1,752,404			1,607,689
Consolidated statement of equity as of December 31, 2013:
	Common shares	$	986		$	950
	Additional paid-in capital	5,015,904			4,841,800
	Treasury shares	(317,356		)	—
	Retained earnings	1,619,150			1,475,934
Consolidated statement of equity as of December 31, 2012:
	Common shares	$	950		$	913
	Additional paid-in capital	4,667,900			4,490,084
	Treasury shares	(322,858		)	—
	Retained earnings	1,701,092			1,556,087

Schedule of Error Corrections and Prior Period Adjustments

The accompanying consolidated balance sheet of the Operating Partnership as of December 31, 2014 and the related statements of capital have been revised to correct the misclassification as follows (amounts in thousands):

		As Previously Reported		As Adjusted
Consolidated balance sheet as of December 31, 2014:
Mezzanine equity
	Limited partner interests in SLGOP	$	—	$	469,524
Capital
	SL Green partner's capital	7,078,924		6,722,422
	Limited partner interests in SLGOP	113,298		—

		Partners' Interest
		Common Units	Common Unitholders
Balance at December 31, 2012 - as previously reported		91,250	$	6,189,529
	Cumulative Adjustment to carry limited partner interests in mezzanine equity at fair value	—	(142,445		)
Balance at December 31, 2012 - as adjusted		91,250	$	6,047,084
Balance at December 31, 2013 - as previously reported		94,993	$	6,506,747
	Cumulative Adjustment to carry limited partner interests in mezzanine equity at fair value	—	(188,063		)
Balance at December 31, 2013 - as adjusted		94,993	$	6,318,684
Balance at December 31, 2014 - as previously reported		97,325	$	7,078,924
	Cumulative Adjustment to carry limited partner interests in mezzanine equity at fair value	—	(356,502		)
Balance at December 31, 2014 - as adjusted		97,325	$	6,722,422