XML 44 R40.htm IDEA: XBRL DOCUMENT
v3.19.3.a.u2

Significant Accounting Policies (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2019
Accounting Policies [Abstract] |
Schedule of estimated useful lives | Properties other than Right of use assets - operating leases 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
Right of use assets - financing leases |  | lesser of 40 years or 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, 2019 and 2018 (in thousands):
| December 31,
| 2019 |  | 2018
Identified intangible assets (included in other assets): |  |  |
Gross amount | $ | 255,198 |  |  | $ | 266,540 |
Accumulated amortization | (228,223 | ) |  | (241,040 | )
Net(1) | $ | 26,975 |  |  | $ | 25,500 |
Identified intangible liabilities (included in deferred revenue): |  |  |
Gross amount | $ | 282,048 |  |  | $ | 276,245 |
Accumulated amortization | (249,514 | ) |  | (253,767 | )
Net(1) | $ | 32,534 |  |  | $ | 22,478 |
(1) | As of December 31, 2019, no net intangible assets and no net intangible liabilities were reclassified to assets held for sale and liabilities related to assets held for sale. As of December 31, 2018, no net intangible assets and no net intangible liabilities 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):
2020 |  | $ | (4,320 | )
2021 |  | (2,748 | )
2022 |  | (2,224 | )
2023 |  | (1,301 | )
2024 |  | (834 | )
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):
2020 |  | $ | 5,183 |
2021 |  | 3,638 |
2022 |  | 2,064 |
2023 |  | 1,435 |
2024 |  | 1,040 |
Schedule of marketable securities | At December 31, 2019 and 2018, we held the following marketable securities (in thousands):
| December 31,
| 2019 |  | 2018
Commercial mortgage-backed securities | $ | 29,887 |  |  | $ | 28,638 |
Total marketable securities available-for-sale | $ | 29,887 |  |  | $ | 28,638 |
Schedules of concentration of risk, by risk factor | For the years ended December 31, 2019, 2018, and 2017, the following properties contributed more than 5.0% of our annualized cash rent from office properties, including our share of annualized cash rent from joint venture office properties:
Property | 2019 | Property | 2018 | Property | 2017
1185 Avenue of the Americas | 7.6% | 11 Madison Avenue | 7.4% | 11 Madison Avenue | 7.1%
11 Madison Avenue | 7.4% | 1185 Avenue of the Americas | 6.7% | 1185 Avenue of the Americas | 7.1%
420 Lexington Avenue | 6.6% | 420 Lexington Avenue | 6.5% | 1515 Broadway | 7.0%
1515 Broadway | 6.1% | 1515 Broadway | 6.0% | 420 Lexington Avenue | 6.0%
One Madison Avenue | 6.0% | One Madison Avenue | 5.8% | One Madison Avenue | 5.6%
220 East 42 nd Street | 5.5% |  |  |  |

X
- Definition Tabular disclosure of the amount of amortization expense expected to be recorded in succeeding fiscal years for acquired below-market leases, net of acquired above-market leases. + References No definition available. + Details
Name: | slg_ScheduleOfAcquiredAboveMarketAndBelowMarketLeasesFutureAmortizationExpenseTableTextBlock
Namespace Prefix: | slg_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the aggregate amount of intangible assets and liabilities. + References No definition available. + Details
Name: | slg_ScheduleOfIntangibleAssetsAndLiabilitiesTableTextBlock
Namespace Prefix: | slg_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the amount of amortization expense expected to be recorded in succeeding fiscal years for all identifiable assets other than acquired below-market leases and acquired above-market leases. + References No definition available. + Details
Name: | slg_ScheduleOfOtherIdentifiableAssetsFutureAmortizationExpenseTableTextBlock
Namespace Prefix: | slg_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -URI http://asc.fasb.org/topic&trid=2196928 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of physical assets used in the normal conduct of business and not intended for resale. Includes, but is not limited to, balances by class of assets, depreciation and depletion expense and method used, including composite depreciation, and accumulated deprecation. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(13)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229 + Details
Name: | us-gaap_PropertyPlantAndEquipmentTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the nature of a concentration, a benchmark to which it is compared, and the percentage that the risk is to the benchmark. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13537-108611 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=118260190&loc=d3e13531-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 16 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6327-108592 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592 Reference 6: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 21 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6442-108592 + Details
Name: | us-gaap_SchedulesOfConcentrationOfRiskByRiskFactorTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration