XML 89 R69.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Significant Accounting Policies - Depreciation and Amortization of Right of Use Assets (Narrative) (Details) - USD ($) | 12 Months Ended |  |  |
--- | --- | --- | --- | ---
Dec. 31, 2023 | Dec. 31, 2022 | Dec. 31, 2021 | Jul. 01, 2022 | Jun. 30, 2022 | Dec. 31, 2020
Franchisor Disclosure [Line Items] |  |  |  |  |  |
Depreciation expense (including amortization of the capital lease asset) | $ 221,000,000 | $ 190,100,000 | $ 187,300,000 |  |  |
Carrying value of investment in leasehold interest | 7,056,100,000 | 9,198,799,000 | 7,650,907,000 |  |  | $ 7,355,079,000
Amortization of above and below Market Leases | 14,200,000 | $ 5,700,000 | $ 4,200,000 |  |  |
625 Madison Avenue |  |  |  |  |  |
Franchisor Disclosure [Line Items] |  |  |  |  |  |
Operating lease rent |  |  |  | $ 20,250,000 | $ 4,610,000 |
Write down of value in leasehold interest | 249,500,000 |  |  |  |  |
Carrying value of investment in leasehold interest | $ 0 |  |  |  |  |

X
- Definition The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production related to Commercial Real Estate Properties. + References No definition available. + Details
Name: | slg_CommercialRealEstatePropertiesDepreciationandAmortization
Namespace Prefix: | slg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Operating Lease, Annual Expense + References No definition available. + Details
Name: | slg_OperatingLeaseAnnualExpense
Namespace Prefix: | slg_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Represents the increase (decrease) in rental revenue during the period resulting from the net amortization of acquired above-market and below-market leases. + References No definition available. + Details
Name: | slg_RentalRevenueIncreaseDecreaseAcquiredLeaseAmortization
Namespace Prefix: | slg_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_FranchisorDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount, before accumulated depreciation, of real estate investment by entity with substantial portion of business acquiring and holding investment real estate or interest in real estate. Excludes real estate not held as investment or interest. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Column E)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 + Details
Name: | us-gaap_RealEstateGrossAtCarryingValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of write-down or reserve recognized in the income statement on real estate investments for entities with a substantial portion of business acquiring and holding investment real estate. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Topic 970 -SubTopic 360 -Name Accounting Standards Codification -Section S99 -Paragraph 1 -Subparagraph (SX 210.12-28(Footnote 5)) -Publisher FASB -URI https://asc.fasb.org//1943274/2147479438/970-360-S99-1 + Details
Name: | us-gaap_SECScheduleIIIRealEstateWritedownOrReserveAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | srt_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=slg_MadisonAvenue625Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |