Organization and Basis of Presentation (Details) - SL Green Operating Partnership	Sep. 30, 2015	Dec. 31, 2014
Organization
Percentage of ownership in SL Green Management LLC owned by operating partnership (percent)	100.00%
Noncontrolling interest in the operating partnership (as a percent)	3.74%	3.92%
Service Corporation
Organization
Economic interest in variable interest entity (as a percent)	95.00%

-- None. No documentation exists for this element. --

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- Definition

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

+ References

No definition available.

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- Definition

The number of units or percentage investment held in the subsidiary by the limited liability company or limited partnership.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 946

-SubTopic 320

-Section S99

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=50485924&loc=d3e611443-123010

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- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 5A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=52262685&loc=SL6759159-111685

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