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Represents the low end of the range of annual vesting rates that occurs once performance criteria are reached.

No definition available.

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Represents the low end of the range of annual vesting rates that occurs once performance criteria are reached.

No definition available.

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Represents the duration of each offering period during which the shares are offered for purchase under the stock-based compensation plan of the entity.

No definition available.

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Share Based Compensation Arrangement by Share Based Payment Award, Fungible Units For Each Share

No definition available.

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Represents the weighted average fair value of awards granted during the period.

No definition available.

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Represents the number of shares that would be issued under the plan if shares issued is equal to fungible units; actual shares issued may be more or less depending on the type of awards issued and the ratio of fungible units to shares under each award.

No definition available.

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Represents the period from the date of grant of the awards for the commencement of vesting of awards.

No definition available.

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Represents the maximum number of fungible units authorized to be granted by the entity.

No definition available.

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Share Based Compensation Arrangement by Share Based Payment Award, Preferred Unit Distributions as a Percentage of Common Unit Distributions

No definition available.

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Share-based Compensation Arrangement By Share-based Payment Award, Number Of Fungible Units Available For Grant

No definition available.

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Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Number of common stock held in a trust that has been set up specifically to accumulate stock for the sole purpose of distribution to participating employees but not yet earned.

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Number of shares issued pursuant to the terms of a deferred compensation arrangement.

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Amount of cost capitalized for award under share-based payment arrangement.

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Amount of cost not yet recognized for nonvested award under share-based payment arrangement.

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Weighted-average period over which cost not yet recognized is expected to be recognized for award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Period over which grantee's right to exercise award under share-based payment arrangement is no longer contingent on satisfaction of service or performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days. Includes, but is not limited to, combination of market, performance or service condition.

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Discount rate from fair value on offering date that participants pay for shares.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Net number of share options (or share units) granted during the period.

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Period from grant date that an equity-based award expires, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Expected term of award under share-based payment arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Weighted average remaining contractual term for option awards outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Data Type:	na
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Data Type:	na
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Data Type:	na
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Name:	us-gaap_AwardTypeAxis=slg_OtherAwardsMember
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Data Type:	na
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Data Type:	na
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