$SLG
SL Green Realty Corp Stock $slg

$slg Overview Financials Valuation SEC Filings Company Website

2020 Q4 Form 10-Q Financial Statement

#000104097120000030 Filed on November 06, 2020

Income Statement

Concept	2020 Q4	2020 Q3	2019 Q3
Revenue	$234.9M	$249.8M	$313.6M
YoY Change	-23.75%	-20.34%	1.98%
Cost Of Revenue	$93.90M	$96.40M	$117.8M
YoY Change	-18.28%	-18.17%	2.26%
Gross Profit	$141.0M	$153.4M	$195.9M
YoY Change	-27.02%	-21.69%	1.82%
Gross Profit Margin	60.03%	61.4%	62.46%
Selling, General & Admin	$25.20M	$23.60M	$23.80M
YoY Change	-2.7%	-0.84%	15.53%
% of Gross Profit	17.87%	15.38%	12.15%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$60.50M	$95.60M	$73.50M
YoY Change	-9.97%	30.07%	0.14%
% of Gross Profit	42.91%	62.32%	37.52%
Operating Expenses	$90.40M	$23.60M	$23.80M
YoY Change	0.44%	-0.84%	15.53%
Operating Profit	$50.60M	$129.8M	$172.1M
YoY Change	-50.97%	-24.58%	0.17%
Interest Expense	$151.7M	$42.60M	$63.61M
YoY Change	-354.1%	-33.03%	-0.74%
% of Operating Profit	299.8%	32.82%	36.96%
Other Income/Expense, Net	-$53.80M	-$6.600M	-$7.000M
YoY Change		-5.71%	4.48%
Pretax Income	$200.3M	$20.70M	$40.70M
YoY Change	724.28%	-49.14%	-59.1%
Income Tax		$0.00	-$1.000M
% Of Pretax Income		0.0%	-2.46%
Net Earnings	$176.6M	$17.60M	$36.90M
YoY Change	734.24%	-52.31%	-59.87%
Net Earnings / Revenue	75.18%	7.04%	11.76%
Basic Earnings Per Share		$0.19	$0.40
Diluted Earnings Per Share	$2.339M	$0.19	$0.40
COMMON SHARES
Basic Shares Outstanding	72.57M shares	70.94M shares	82.29M shares
Diluted Shares Outstanding		75.41M shares	86.71M shares

Balance Sheet

Concept	2020 Q4	2020 Q3	2019 Q3
SHORT-TERM ASSETS
Cash & Short-Term Investments	$294.6M	$249.1M	$152.0M
YoY Change	50.35%	63.95%	-19.51%
Cash & Equivalents	$266.1M	$221.4M	$121.8M
Short-Term Investments	$28.57M	$27.73M	$30.21M
Other Short-Term Assets
YoY Change
Inventory	$0.00	$0.00	$403.0M
Prepaid Expenses
Receivables	$382.0M	$409.0M	$371.0M
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$648.0M	$630.0M	$896.0M
YoY Change	-28.48%	-29.69%	-28.38%
LONG-TERM ASSETS
Property, Plant & Equipment	$5.399B	$6.761B	$6.941B
YoY Change	-19.71%	-2.59%	6.38%
Goodwill
YoY Change
Intangibles
YoY Change
Long-Term Investments	$3.823B	$2.947B	$2.924B
YoY Change	31.26%	0.79%	-4.79%
Other Assets	$284.0M	$289.0M	$277.0M
YoY Change	1.07%	4.33%	-7.97%
Total Long-Term Assets	$11.06B	$11.69B	$12.40B
YoY Change	-6.75%	-5.69%	1.6%
TOTAL ASSETS
Total Short-Term Assets	$648.0M	$630.0M	$896.0M
Total Long-Term Assets	$11.06B	$11.69B	$12.40B
Total Assets	$11.71B	$12.32B	$13.29B
YoY Change	-8.29%	-7.3%	-1.19%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$151.0M	$153.0M	$143.0M
YoY Change	-9.58%	6.99%	1.42%
Accrued Expenses	$354.0M	$382.0M	$412.0M
YoY Change	-12.38%	-7.28%	1425.93%
Deferred Revenue
YoY Change
Short-Term Debt	$0.00	$0.00	$0.00
YoY Change
Long-Term Debt Due
YoY Change
Total Short-Term Liabilities	$708.0M	$617.0M	$696.0M
YoY Change	-0.7%	-11.35%	120.95%
LONG-TERM LIABILITIES
Long-Term Debt	$5.081B	$5.594B	$5.880B
YoY Change	-8.5%	-4.86%	5.3%
Other Long-Term Liabilities	$421.0M	$424.0M	$267.0M
YoY Change	44.67%	58.8%	-48.55%
Total Long-Term Liabilities	$5.502B	$6.018B	$6.147B
YoY Change	-5.85%	-2.1%	0.72%
TOTAL LIABILITIES
Total Short-Term Liabilities	$708.0M	$617.0M	$696.0M
Total Long-Term Liabilities	$5.502B	$6.018B	$6.147B
Total Liabilities	$6.211B	$6.634B	$6.844B
YoY Change	-5.26%	-3.06%	6.62%
SHAREHOLDERS EQUITY
Retained Earnings	$1.015B	$1.035B	$1.226B
YoY Change	-6.38%	-15.56%	-17.0%
Common Stock	$716.0K	$741.0K	$826.0K
YoY Change	-10.83%	-10.29%	-4.73%
Preferred Stock
YoY Change
Treasury Stock (at cost)	$124.0M	$124.0M	$124.0M
YoY Change	0.0%	0.0%	0.0%
Treasury Stock Shares	996.0K shares	1.055M shares	1.055M shares
Shareholders Equity	$4.910B	$5.056B	$5.692B
YoY Change
Total Liabilities & Shareholders Equity	$11.71B	$12.32B	$13.29B
YoY Change	-8.29%	-7.3%	-1.19%

Cashflow Statement

Concept	2020 Q4	2020 Q3	2019 Q3
OPERATING ACTIVITIES
Net Income	$176.6M	$17.60M	$36.90M
YoY Change	734.24%	-52.31%	-59.87%
Depreciation, Depletion And Amortization	$60.50M	$95.60M	$73.50M
YoY Change	-9.97%	30.07%	0.14%
Cash From Operating Activities	$226.3M	$103.6M	$81.50M
YoY Change	193.51%	27.12%	14.31%
INVESTING ACTIVITIES
Capital Expenditures	-$176.5M	-$98.40M	-$56.90M
YoY Change	70.86%	72.93%	-41.76%
Acquisitions
YoY Change
Other Investing Activities	$857.9M	$69.50M	$282.4M
YoY Change	87.03%	-75.39%	-14.4%
Cash From Investing Activities	$681.4M	-$28.80M	$225.5M
YoY Change	91.73%	-112.77%	-2.84%
FINANCING ACTIVITIES
Cash Dividend Paid
YoY Change
Common Stock Issuance & Retirement, Net
YoY Change
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-839.4M	-871.6M	-331.6M
YoY Change	105.94%	162.85%	-21.96%
NET CHANGE
Cash From Operating Activities	226.3M	103.6M	81.50M
Cash From Investing Activities	681.4M	-28.80M	225.5M
Cash From Financing Activities	-839.4M	-871.6M	-331.6M
Net Change In Cash	68.30M	-796.8M	-24.60M
YoY Change	174.3%	3139.02%	-79.75%
FREE CASH FLOW
Cash From Operating Activities	$226.3M	$103.6M	$81.50M
Capital Expenditures	-$176.5M	-$98.40M	-$56.90M
Free Cash Flow	$402.8M	$202.0M	$138.4M
YoY Change	123.28%	45.95%	-18.11%

Facts In Submission

Frame	Concept Type	Concept / XBRL Key	Value	Unit
	dei	Entity Central Index Key EntityCentralIndexKey	0001040971
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q3
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Amendment Flag AmendmentFlag	false
CY2020Q4	dei	Entity Common Stock Shares Outstanding EntityCommonStockSharesOutstanding	72569561	shares
	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Entity File Number EntityFileNumber	1-13199
	dei	Entity Registrant Name EntityRegistrantName	SL GREEN REALTY CORP
	dei	Document Period End Date DocumentPeriodEndDate	2020-09-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	MD
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	13-3956775
	dei	Entity Address Address Line1 EntityAddressAddressLine1	420 Lexington Avenue
	dei	Entity Address City Or Town EntityAddressCityOrTown	New York
	dei	Entity Address State Or Province EntityAddressStateOrProvince	NY
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	10170
	dei	City Area Code CityAreaCode	212
	dei	Local Phone Number LocalPhoneNumber	594-2700
	dei	Entity Current Reporting Status EntityCurrentReportingStatus	Yes
	dei	Entity Interactive Data Current EntityInteractiveDataCurrent	Yes
	dei	Entity Filer Category EntityFilerCategory	Large Accelerated Filer
	dei	Entity Small Business EntitySmallBusiness	false
	dei	Entity Emerging Growth Company EntityEmergingGrowthCompany	false
	dei	Entity Shell Company EntityShellCompany	false
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	us-gaap	Depreciation And Amortization DepreciationAndAmortization	208268000	USD
CY2020Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	8957000	USD
CY2019Q3	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	0	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	27018000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	0	USD
CY2020Q3	slg	Transaction Related Costs TransactionRelatedCosts	45000	USD
CY2019Q3	slg	Transaction Related Costs TransactionRelatedCosts	44000	USD
	slg	Transaction Related Costs TransactionRelatedCosts	483000	USD
	slg	Transaction Related Costs TransactionRelatedCosts	360000	USD
CY2020Q3	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	23602000	USD
CY2019Q3	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	23841000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	66682000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	75300000	USD
CY2020Q3	slg	Total Costs And Expenses Including Nonoperating Income Expense TotalCostsAndExpensesIncludingNonoperatingIncomeExpense	248212000	USD
CY2019Q3	slg	Total Costs And Expenses Including Nonoperating Income Expense TotalCostsAndExpensesIncludingNonoperatingIncomeExpense	263341000	USD
	slg	Total Costs And Expenses Including Nonoperating Income Expense TotalCostsAndExpensesIncludingNonoperatingIncomeExpense	744980000	USD
	slg	Total Costs And Expenses Including Nonoperating Income Expense TotalCostsAndExpensesIncludingNonoperatingIncomeExpense	782052000	USD
CY2020Q3	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-432000	USD
CY2019Q3	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-9864000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-15445000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-22644000	USD
CY2020Q3	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	0	USD
CY2019Q3	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	0	USD
	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	0	USD
	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	76181000	USD
CY2020Q3	slg	Purchase Price Fair Value Adjustment Gross PurchasePriceFairValueAdjustmentGross	0	USD
CY2019Q3	slg	Purchase Price Fair Value Adjustment Gross PurchasePriceFairValueAdjustmentGross	3799000	USD
	slg	Purchase Price Fair Value Adjustment Gross PurchasePriceFairValueAdjustmentGross	0	USD
	slg	Purchase Price Fair Value Adjustment Gross PurchasePriceFairValueAdjustmentGross	69389000	USD
CY2020Q3	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	26104000	USD
CY2019Q3	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	3541000	USD
	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	163624000	USD
	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	2492000	USD
CY2020Q3	slg	Depreciable Real Estate Reserves And Impairment DepreciableRealEstateReservesAndImpairment	6627000	USD
CY2019Q3	slg	Depreciable Real Estate Reserves And Impairment DepreciableRealEstateReservesAndImpairment	7047000	USD
	slg	Depreciable Real Estate Reserves And Impairment DepreciableRealEstateReservesAndImpairment	6627000	USD
	slg	Depreciable Real Estate Reserves And Impairment DepreciableRealEstateReservesAndImpairment	7047000	USD
CY2020Q3	us-gaap	Profit Loss ProfitLoss	20677000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	40722000	USD
	us-gaap	Profit Loss ProfitLoss	214418000	USD
	us-gaap	Profit Loss ProfitLoss	267232000	USD
CY2020Q3	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Redeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsRedeemable	802000	USD
CY2019Q3	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Redeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsRedeemable	1719000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Redeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsRedeemable	10073000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Redeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsRedeemable	12306000	USD
CY2020Q3	us-gaap	Noncontrolling Interest In Net Income Loss Other Noncontrolling Interests Redeemable NoncontrollingInterestInNetIncomeLossOtherNoncontrollingInterestsRedeemable	414000	USD
CY2019Q3	us-gaap	Noncontrolling Interest In Net Income Loss Other Noncontrolling Interests Redeemable NoncontrollingInterestInNetIncomeLossOtherNoncontrollingInterestsRedeemable	-624000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Other Noncontrolling Interests Redeemable NoncontrollingInterestInNetIncomeLossOtherNoncontrollingInterestsRedeemable	1145000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Other Noncontrolling Interests Redeemable NoncontrollingInterestInNetIncomeLossOtherNoncontrollingInterestsRedeemable	-2524000	USD
CY2020Q3	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Redeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersRedeemable	1864000	USD
CY2019Q3	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Redeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersRedeemable	2732000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Redeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersRedeemable	6883000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Redeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersRedeemable	8185000	USD
CY2020Q3	us-gaap	Net Income Loss NetIncomeLoss	17597000	USD
CY2019Q3	us-gaap	Net Income Loss NetIncomeLoss	36895000	USD
	us-gaap	Net Income Loss NetIncomeLoss	196317000	USD
	us-gaap	Net Income Loss NetIncomeLoss	249265000	USD
CY2020Q3	us-gaap	Dividends Preferred Stock DividendsPreferredStock	3738000	USD
CY2019Q3	us-gaap	Dividends Preferred Stock DividendsPreferredStock	3738000	USD
	us-gaap	Dividends Preferred Stock DividendsPreferredStock	11213000	USD
	us-gaap	Dividends Preferred Stock DividendsPreferredStock	11213000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	13859000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	33157000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	185104000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	238052000	USD
CY2020Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.19
CY2019Q3	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.40
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.44
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.87
CY2020Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.19
CY2019Q3	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.40
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.44
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.87
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	73020000	shares
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	82292000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	75521000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	82855000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	77491000	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	86714000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	80085000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	87309000	shares
CY2020Q3	us-gaap	Profit Loss ProfitLoss	20677000	USD
CY2019Q3	us-gaap	Profit Loss ProfitLoss	40722000	USD
	us-gaap	Profit Loss ProfitLoss	214418000	USD
	us-gaap	Profit Loss ProfitLoss	267232000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	6099000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-12574000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-48227000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-59680000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	389000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	230000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-2152000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	1571000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	6488000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-12344000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-50379000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-58109000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	27165000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	28378000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	164039000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	209123000	USD
CY2020Q3	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	3080000	USD
CY2019Q3	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	3827000	USD
	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	18101000	USD
	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	17967000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest	317000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest	-607000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest	-2664000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest	-2869000	USD
CY2020Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	23768000	USD
CY2019Q3	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	25158000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	148602000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	194025000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5517198000	USD
	slg	Profit Loss Less Minority Interest In Net Income Loss Operating Partnerships ProfitLossLessMinorityInterestInNetIncomeLossOperatingPartnerships	179451000	USD
	us-gaap	Minority Interest Decrease From Redemptions MinorityInterestDecreaseFromRedemptions	1536000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-53886000	USD
	us-gaap	Dividends Preferred Stock DividendsPreferredStock	7475000	USD
	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	364000	USD
	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	8744000	USD
	slg	Reallocationof Noncontrolling Interest In Operating Partnership Increase Decrease ReallocationofNoncontrollingInterestInOperatingPartnershipIncreaseDecrease	31144000	USD
	slg	Deferred Compensation Plan And Stock Award Net DeferredCompensationPlanAndStockAwardNet	13493000	USD
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	360868000	USD
	slg	Consolidation Of Joint Venture Interest ConsolidationOfJointVentureInterest	8185000	USD
	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	596000	USD
CY2020Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.180
	us-gaap	Dividends Common Stock DividendsCommonStock	89272000	USD
CY2020Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5205762000	USD
CY2020Q3	slg	Profit Loss Less Minority Interest In Net Income Loss Operating Partnerships ProfitLossLessMinorityInterestInNetIncomeLossOperatingPartnerships	18011000	USD
CY2020Q3	us-gaap	Minority Interest Decrease From Redemptions MinorityInterestDecreaseFromRedemptions	0	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	6171000	USD
CY2020Q3	us-gaap	Dividends Preferred Stock DividendsPreferredStock	3738000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	202000	USD
CY2020Q3	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	0	USD
CY2020Q3	slg	Reallocationof Noncontrolling Interest In Operating Partnership Increase Decrease ReallocationofNoncontrollingInterestInOperatingPartnershipIncreaseDecrease	4109000	USD
CY2020Q3	slg	Deferred Compensation Plan And Stock Award Net DeferredCompensationPlanAndStockAwardNet	7543000	USD
CY2020Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	31127000	USD
CY2020Q3	slg	Consolidation Of Joint Venture Interest ConsolidationOfJointVentureInterest	4219000	USD
CY2020Q3	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	12530000	USD
CY2020Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.885
CY2020Q3	us-gaap	Dividends Common Stock DividendsCommonStock	64617000	USD
CY2020Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5134005000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5947855000	USD
	slg	Profit Loss Less Minority Interest In Net Income Loss Operating Partnerships ProfitLossLessMinorityInterestInNetIncomeLossOperatingPartnerships	210470000	USD
	us-gaap	Minority Interest Decrease From Redemptions MinorityInterestDecreaseFromRedemptions	25791000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-43503000	USD
	us-gaap	Dividends Preferred Stock DividendsPreferredStock	7475000	USD
	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	263000	USD
	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	446000	USD
	slg	Reallocationof Noncontrolling Interest In Operating Partnership Increase Decrease ReallocationofNoncontrollingInterestInOperatingPartnershipIncreaseDecrease	-14028000	USD
	slg	Deferred Compensation Plan And Stock Award Net DeferredCompensationPlanAndStockAwardNet	10533000	USD
	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	109313000	USD
	slg	Consolidation Of Joint Venture Interest ConsolidationOfJointVentureInterest	50692000	USD
	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	271000	USD
CY2019Q2	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	1.70
	us-gaap	Dividends Common Stock DividendsCommonStock	140377000	USD
CY2019Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5879501000	USD
CY2019Q3	slg	Profit Loss Less Minority Interest In Net Income Loss Operating Partnerships ProfitLossLessMinorityInterestInNetIncomeLossOperatingPartnerships	36271000	USD
CY2019Q3	us-gaap	Minority Interest Decrease From Redemptions MinorityInterestDecreaseFromRedemptions	54000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-11737000	USD
CY2019Q3	us-gaap	Dividends Preferred Stock DividendsPreferredStock	3738000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	39000	USD
CY2019Q3	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	25000	USD
CY2019Q3	slg	Reallocationof Noncontrolling Interest In Operating Partnership Increase Decrease ReallocationofNoncontrollingInterestInOperatingPartnershipIncreaseDecrease	-1481000	USD
CY2019Q3	slg	Deferred Compensation Plan And Stock Award Net DeferredCompensationPlanAndStockAwardNet	5948000	USD
CY2019Q3	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	74531000	USD
CY2019Q3	slg	Consolidation Of Joint Venture Interest ConsolidationOfJointVentureInterest	2404000	USD
CY2019Q3	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	207000	USD
CY2019Q3	us-gaap	Common Stock Dividends Per Share Declared CommonStockDividendsPerShareDeclared	0.85
CY2019Q3	us-gaap	Dividends Common Stock DividendsCommonStock	69140000	USD
CY2019Q3	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5763300000	USD
	us-gaap	Profit Loss ProfitLoss	214418000	USD
	us-gaap	Profit Loss ProfitLoss	267232000	USD
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	265048000	USD
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	216834000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-15445000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-22644000	USD
	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	576000	USD
	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	648000	USD
	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	0	USD
	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	76181000	USD
	slg	Purchase Price Fair Value Adjustment Gain Loss PurchasePriceFairValueAdjustmentGainLoss	0	USD
	slg	Purchase Price Fair Value Adjustment Gain Loss PurchasePriceFairValueAdjustmentGainLoss	69389000	USD
	slg	Depreciable Real Estate Reserves And Impairment DepreciableRealEstateReservesAndImpairment	6627000	USD
	slg	Depreciable Real Estate Reserves And Impairment DepreciableRealEstateReservesAndImpairment	7047000	USD
	us-gaap	Gains Losses On Sales Of Investment Real Estate GainsLossesOnSalesOfInvestmentRealEstate	163624000	USD
	us-gaap	Gains Losses On Sales Of Investment Real Estate GainsLossesOnSalesOfInvestmentRealEstate	2492000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	27018000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	0	USD
	us-gaap	Straight Line Rent StraightLineRent	3459000	USD
	us-gaap	Straight Line Rent StraightLineRent	10005000	USD
	slg	Non Cash Lease Expense NonCashLeaseExpense	9735000	USD
	slg	Non Cash Lease Expense NonCashLeaseExpense	10255000	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-14874000	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	11766000	USD
	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	43069000	USD
	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	7564000	USD
	us-gaap	Increase Decrease In Due From Related Parties Current IncreaseDecreaseInDueFromRelatedPartiesCurrent	-4195000	USD
	us-gaap	Increase Decrease In Due From Related Parties Current IncreaseDecreaseInDueFromRelatedPartiesCurrent	-8921000	USD
	us-gaap	Increase Decrease In Deferred Leasing Fees IncreaseDecreaseInDeferredLeasingFees	12472000	USD
	us-gaap	Increase Decrease In Deferred Leasing Fees IncreaseDecreaseInDeferredLeasingFees	38542000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	55301000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	47139000	USD
	slg	Increase Decrease In Accrued Liabilities And Other IncreaseDecreaseInAccruedLiabilitiesAndOther	43256000	USD
	slg	Increase Decrease In Accrued Liabilities And Other IncreaseDecreaseInAccruedLiabilitiesAndOther	18737000	USD
	us-gaap	Increase Decrease In Deferred Liabilities IncreaseDecreaseInDeferredLiabilities	13206000	USD
	us-gaap	Increase Decrease In Deferred Liabilities IncreaseDecreaseInDeferredLiabilities	18255000	USD
	slg	Increase Decrease In Operating Lease Liability IncreaseDecreaseInOperatingLeaseLiability	-8530000	USD
	slg	Increase Decrease In Operating Lease Liability IncreaseDecreaseInOperatingLeaseLiability	-8062000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	327943000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	299433000	USD
	us-gaap	Payments To Acquire Commercial Real Estate PaymentsToAcquireCommercialRealEstate	86846000	USD
	us-gaap	Payments To Acquire Commercial Real Estate PaymentsToAcquireCommercialRealEstate	261596000	USD
	slg	Payments To Acquire Land Buildings And Improvements PaymentsToAcquireLandBuildingsAndImprovements	281651000	USD
	slg	Payments To Acquire Land Buildings And Improvements PaymentsToAcquireLandBuildingsAndImprovements	150742000	USD
	slg	Payments For Acquisition Deposits And Deferred Purchase Price PaymentsForAcquisitionDepositsAndDeferredPurchasePrice	0	USD
	slg	Payments For Acquisition Deposits And Deferred Purchase Price PaymentsForAcquisitionDepositsAndDeferredPurchasePrice	228000	USD
	us-gaap	Payments To Acquire Equity Method Investments PaymentsToAcquireEquityMethodInvestments	39724000	USD
	us-gaap	Payments To Acquire Equity Method Investments PaymentsToAcquireEquityMethodInvestments	114050000	USD
	slg	Proceeds From Equity Method Investment Dividends Or Distributions ProceedsFromEquityMethodInvestmentDividendsOrDistributions	104300000	USD
	slg	Proceeds From Equity Method Investment Dividends Or Distributions ProceedsFromEquityMethodInvestmentDividendsOrDistributions	62576000	USD
	us-gaap	Proceeds From Real Estate And Real Estate Joint Ventures ProceedsFromRealEstateAndRealEstateJointVentures	333037000	USD
	us-gaap	Proceeds From Real Estate And Real Estate Joint Ventures ProceedsFromRealEstateAndRealEstateJointVentures	138948000	USD
	slg	Payments For Proceeds From Other Investments PaymentsForProceedsFromOtherInvestments	3921000	USD
	slg	Payments For Proceeds From Other Investments PaymentsForProceedsFromOtherInvestments	2491000	USD
	us-gaap	Payments To Acquire Investments PaymentsToAcquireInvestments	353797000	USD
	us-gaap	Payments To Acquire Investments PaymentsToAcquireInvestments	555951000	USD
	slg	Repayments Or Redemption Of Debt And Preferred Equity Investments RepaymentsOrRedemptionOfDebtAndPreferredEquityInvestments	703625000	USD
	slg	Repayments Or Redemption Of Debt And Preferred Equity Investments RepaymentsOrRedemptionOfDebtAndPreferredEquityInvestments	642634000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	375023000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-240900000	USD
	us-gaap	Proceeds From Issuance Of Secured Debt ProceedsFromIssuanceOfSecuredDebt	1128775000	USD
	us-gaap	Proceeds From Issuance Of Secured Debt ProceedsFromIssuanceOfSecuredDebt	699072000	USD
	us-gaap	Repayments Of Secured Debt RepaymentsOfSecuredDebt	710352000	USD
	us-gaap	Repayments Of Secured Debt RepaymentsOfSecuredDebt	162024000	USD
	us-gaap	Proceeds From Other Debt ProceedsFromOtherDebt	1275000000	USD
	us-gaap	Proceeds From Other Debt ProceedsFromOtherDebt	1090000000	USD
	us-gaap	Repayments Of Other Debt RepaymentsOfOtherDebt	1575000000	USD
	us-gaap	Repayments Of Other Debt RepaymentsOfOtherDebt	1255000000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	566000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	302000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	381992000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	175005000	USD
	us-gaap	Payments For Repurchase Of Redeemable Preferred Stock PaymentsForRepurchaseOfRedeemablePreferredStock	82750000	USD
	us-gaap	Payments For Repurchase Of Redeemable Preferred Stock PaymentsForRepurchaseOfRedeemablePreferredStock	15142000	USD
	slg	Payments For Repurchase Of Partnership Units PaymentsForRepurchaseOfPartnershipUnits	18913000	USD
	slg	Payments For Repurchase Of Partnership Units PaymentsForRepurchaseOfPartnershipUnits	15918000	USD
	slg	Distributions To Noncontrolling Interests Other Partnerships DistributionsToNoncontrollingInterestsOtherPartnerships	13126000	USD
	slg	Distributions To Noncontrolling Interests Other Partnerships DistributionsToNoncontrollingInterestsOtherPartnerships	478000	USD
	slg	Proceeds From Noncontrolling Interests In Other Partnerships ProceedsFromNoncontrollingInterestsInOtherPartnerships	12404000	USD
	slg	Proceeds From Noncontrolling Interests In Other Partnerships ProceedsFromNoncontrollingInterestsInOtherPartnerships	4873000	USD
	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	1536000	USD
	us-gaap	Payments To Minority Shareholders PaymentsToMinorityShareholders	25791000	USD
	slg	Distribution To Noncontrolling Interest Operating Partnership DistributionToNoncontrollingInterestOperatingPartnership	8857000	USD
	slg	Distribution To Noncontrolling Interest Operating Partnership DistributionToNoncontrollingInterestOperatingPartnership	10993000	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	224147000	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	230804000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	4752000	USD
	us-gaap	Payments Related To Tax Withholding For Share Based Compensation PaymentsRelatedToTaxWithholdingForShareBasedCompensation	3126000	USD
	slg	Deferred Loan Costs And Capitalized Lease Obligation DeferredLoanCostsAndCapitalizedLeaseObligation	34687000	USD
	slg	Deferred Loan Costs And Capitalized Lease Obligation DeferredLoanCostsAndCapitalizedLeaseObligation	21068000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	580000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	0	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-639947000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	-121102000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	63019000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-62569000	USD
CY2019Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	241430000	USD
CY2018Q4	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	279113000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	304449000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	216544000	USD
	us-gaap	Partners Capital Account Redemptions PartnersCapitalAccountRedemptions	8744000	USD
	us-gaap	Partners Capital Account Redemptions PartnersCapitalAccountRedemptions	471000	USD
	us-gaap	Transfer Of Investments TransferOfInvestments	119497000	USD
	us-gaap	Transfer Of Investments TransferOfInvestments	0	USD
	slg	Issuance Of Preferred Units Relating To Real Estate Acquisition IssuanceOfPreferredUnitsRelatingToRealEstateAcquisition	0	USD
	slg	Issuance Of Preferred Units Relating To Real Estate Acquisition IssuanceOfPreferredUnitsRelatingToRealEstateAcquisition	1000000	USD
	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	11993000	USD
	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	10040000	USD
	slg	Operating Partnership Noncontrolling Interest Fair Value Adjustment OperatingPartnershipNoncontrollingInterestFairValueAdjustment	35253000	USD
	slg	Operating Partnership Noncontrolling Interest Fair Value Adjustment OperatingPartnershipNoncontrollingInterestFairValueAdjustment	15509000	USD
	slg	Deconsolidation Of Subsidiary DeconsolidationOfSubsidiary	0	USD
	slg	Deconsolidation Of Subsidiary DeconsolidationOfSubsidiary	395000	USD
	slg	Reversal Of Assets Held For Sale ReversalOfAssetsHeldForSale	391664000	USD
	slg	Reversal Of Assets Held For Sale ReversalOfAssetsHeldForSale	0	USD
	slg	Seller Financed Purchases SellerFinancedPurchases	100000000	USD
	slg	Seller Financed Purchases SellerFinancedPurchases	0	USD
	slg	Debt And Preferred Equity Reserves DebtAndPreferredEquityReserves	4638000	USD
	slg	Debt And Preferred Equity Reserves DebtAndPreferredEquityReserves	0	USD
	slg	Transfer To Net Assets Held For Sale TransferToNetAssetsHeldForSale	0	USD
	slg	Transfer To Net Assets Held For Sale TransferToNetAssetsHeldForSale	403488000	USD
	slg	Removalof Fully Depreciated Real Estate Assets RemovalofFullyDepreciatedRealEstateAssets	7906000	USD
	slg	Removalof Fully Depreciated Real Estate Assets RemovalofFullyDepreciatedRealEstateAssets	6602000	USD
CY2020Q3	slg	Finite Lived Intangible Liabilities Gross FiniteLivedIntangibleLiabilitiesGross	273240000	USD
	slg	Increase Decreasein Noncontrolling Interestin Joint Ventures IncreaseDecreaseinNoncontrollingInterestinJointVentures	0	USD
	slg	Increase Decreasein Noncontrolling Interestin Joint Ventures IncreaseDecreaseinNoncontrollingInterestinJointVentures	48223000	USD
	slg	Share Repurchases Payable ShareRepurchasesPayable	10003000	USD
	slg	Share Repurchases Payable ShareRepurchasesPayable	8839000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	57500000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	389120000	USD
CY2020Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	221404000	USD
CY2019Q3	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	121751000	USD
CY2020Q3	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	83045000	USD
CY2019Q3	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	94793000	USD
CY2020Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	304449000	USD
CY2019Q3	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	216544000	USD
CY2020Q3	slg	Numberof Real Estate Buildings NumberofRealEstateBuildings	72	building
CY2020Q3	us-gaap	Area Of Real Estate Property AreaOfRealEstateProperty	30328709	sqft
CY2020Q3	slg	Real Estate Weighted Average Occupancy RealEstateWeightedAverageOccupancy	0.919
CY2020Q3	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	16086000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	26975000	USD
CY2020Q3	slg	Mortgage Loanson Real Estate Commercialand Consumer Net Including Debt Investments Other MortgageLoansonRealEstateCommercialandConsumerNetIncludingDebtInvestmentsOther	1150000000	USD
CY2020Q3	slg	Debt Investments Other DebtInvestmentsOther	100000000	USD
	slg	Number Of Shares On Redemption Of One Unit Of Partnership Interest NumberOfSharesOnRedemptionOfOneUnitOfPartnershipInterest	1	shares
CY2020Q3	slg	Rental Revenue Increase Decrease Acquired Lease Amortization RentalRevenueIncreaseDecreaseAcquiredLeaseAmortization	1600000	USD
	slg	Rental Revenue Increase Decrease Acquired Lease Amortization RentalRevenueIncreaseDecreaseAcquiredLeaseAmortization	4500000	USD
CY2019Q3	slg	Rental Revenue Increase Decrease Acquired Lease Amortization RentalRevenueIncreaseDecreaseAcquiredLeaseAmortization	1200000	USD
	slg	Rental Revenue Increase Decrease Acquired Lease Amortization RentalRevenueIncreaseDecreaseAcquiredLeaseAmortization	3600000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	224221000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	255198000	USD
CY2020Q3	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	208135000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	228223000	USD
CY2019Q4	slg	Finite Lived Intangible Liabilities Gross FiniteLivedIntangibleLiabilitiesGross	282048000	USD
CY2020Q3	slg	Finite Lived Intangible Liabilities Accumulated Amortization FiniteLivedIntangibleLiabilitiesAccumulatedAmortization	255879000	USD
CY2019Q4	slg	Finite Lived Intangible Liabilities Accumulated Amortization FiniteLivedIntangibleLiabilitiesAccumulatedAmortization	249514000	USD
CY2020Q3	slg	Finite Lived Intangible Liabilities Net FiniteLivedIntangibleLiabilitiesNet	17361000	USD
CY2019Q4	slg	Finite Lived Intangible Liabilities Net FiniteLivedIntangibleLiabilitiesNet	32534000	USD
CY2019Q4	slg	Net Intangible Assets Transferredto Assets Heldfor Sale NetIntangibleAssetsTransferredtoAssetsHeldforSale	0	USD
CY2019Q4	slg	Net Intangible Liabilities Transferredto Liabilities Relatedto Assets Heldfor Sale NetIntangibleLiabilitiesTransferredtoLiabilitiesRelatedtoAssetsHeldforSale	0	USD
CY2020Q3	us-gaap	Allowance For Doubtful Accounts Premiums And Other Receivables AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables	9500000	USD
CY2019Q4	us-gaap	Allowance For Doubtful Accounts Premiums And Other Receivables AllowanceForDoubtfulAccountsPremiumsAndOtherReceivables	2600000	USD
CY2020Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	0	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2000000.0	USD
CY2019Q3	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	-1000000.0	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	500000	USD
	us-gaap	Use Of Estimates UseOfEstimates	<div style="margin-bottom:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Use of Estimates</span></div><div style="margin-bottom:6pt;text-align:justify;text-indent:24.75pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">The preparation of financial statements in conformity with accounting principles generally accepted in the United States requires management to make estimates and assumptions that affect the amounts reported in the financial statements and accompanying notes. Actual results could differ from those estimates.</span></div>
	us-gaap	Concentration Risk Credit Risk ConcentrationRiskCreditRisk	<div style="margin-bottom:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Concentrations of Credit Risk</span></div><div style="margin-bottom:6pt;text-align:justify;text-indent:24.75pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Financial instruments that potentially subject us to concentrations of credit risk consist primarily of cash investments, debt and preferred equity investments and accounts receivable. We place our cash investments with high quality financial institutions. The collateral securing our debt and preferred equity investments is located in New York City. See Note 5, "Debt and Preferred Equity Investments." </span></div>We perform initial and ongoing evaluations of the credit quality of our tenants and require most tenants to provide security deposits or letters of credit. Though these security deposits and letters of credit are insufficient to meet the total value of a tenant's lease obligation, they are a measure of good faith and a potential source of funds to offset the economic costs associated with lost revenue from that tenant and the costs associated with re-tenanting a space.
	us-gaap	Prior Period Reclassification Adjustment Description PriorPeriodReclassificationAdjustmentDescription	<div style="margin-bottom:6pt;text-align:justify"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:700;line-height:120%">Reclassification</span></div><div style="margin-bottom:6pt;text-align:justify;text-indent:24.75pt"><span style="color:#000000;font-family:'Times New Roman',sans-serif;font-size:10pt;font-weight:400;line-height:120%">Certain prior year balances have been reclassified to conform to our current year presentation.</span></div>
CY2019Q4	us-gaap	Mortgage Loans On Real Estate MortgageLoansOnRealEstate	1580306000	USD
CY2018Q4	us-gaap	Mortgage Loans On Real Estate MortgageLoansOnRealEstate	2099393000	USD
	us-gaap	Mortgage Loans On Real Estate Amortization Of Premium MortgageLoansOnRealEstateAmortizationOfPremium	956869000	USD
CY2019	us-gaap	Mortgage Loans On Real Estate Amortization Of Premium MortgageLoansOnRealEstateAmortizationOfPremium	1190689000	USD
	slg	Sec Schedule1229 Real Estate Companies Investment In Mortgage Loans On Real Estate Loan Loss Reserve Period Increase Decrease SECSchedule1229RealEstateCompaniesInvestmentInMortgageLoansOnRealEstateLoanLossReservePeriodIncreaseDecrease	-17260000	USD
CY2019	slg	Sec Schedule1229 Real Estate Companies Investment In Mortgage Loans On Real Estate Loan Loss Reserve Period Increase Decrease SECSchedule1229RealEstateCompaniesInvestmentInMortgageLoansOnRealEstateLoanLossReservePeriodIncreaseDecrease	4000000	USD
CY2020Q3	us-gaap	Mortgage Loans On Real Estate MortgageLoansOnRealEstate	1153363000	USD
CY2019Q4	us-gaap	Mortgage Loans On Real Estate MortgageLoansOnRealEstate	1580306000	USD
CY2020Q3	us-gaap	Mortgage Loans On Real Estate Commercial And Consumer Net MortgageLoansOnRealEstateCommercialAndConsumerNet	1153363000	USD
CY2020Q3	slg	Mortgage Loanson Real Estate Senior Financing MortgageLoansonRealEstateSeniorFinancing		USD
CY2019Q4	us-gaap	Allowance For Loan And Lease Losses Real Estate AllowanceForLoanAndLeaseLossesRealEstate	1750000	USD
CY2018Q4	us-gaap	Allowance For Loan And Lease Losses Real Estate AllowanceForLoanAndLeaseLossesRealEstate	5750000	USD
	slg	Debt And Equity Securities Credit Loss Expense Reversal DebtAndEquitySecuritiesCreditLossExpenseReversal	20741000	USD
CY2019	slg	Debt And Equity Securities Credit Loss Expense Reversal DebtAndEquitySecuritiesCreditLossExpenseReversal	0	USD
	slg	Financing Receivable Allowance For Credit Losses Write Offs And Reclassifications FinancingReceivableAllowanceForCreditLossesWriteOffsAndReclassifications	31285000	USD
CY2019	slg	Financing Receivable Allowance For Credit Losses Write Offs And Reclassifications FinancingReceivableAllowanceForCreditLossesWriteOffsAndReclassifications	4000000	USD
CY2020Q3	us-gaap	Allowance For Loan And Lease Losses Real Estate AllowanceForLoanAndLeaseLossesRealEstate	19010000	USD
CY2019Q4	us-gaap	Allowance For Loan And Lease Losses Real Estate AllowanceForLoanAndLeaseLossesRealEstate	1750000	USD
CY2020Q3	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	27700000	USD
CY2020Q3	slg	Debt And Equity Securities Weighted Average Risk Rating DebtAndEquitySecuritiesWeightedAverageRiskRating	1.4
CY2019	slg	Financing Receivable Portfolio Segments Number FinancingReceivablePortfolioSegmentsNumber	1	segment
	slg	Financing Receivable Portfolio Segments Number FinancingReceivablePortfolioSegmentsNumber	1	segment
CY2020Q3	slg	Financing Receivable Recorded In Other Assets FinancingReceivableRecordedInOtherAssets	110900000	USD
CY2019Q4	slg	Financing Receivable Recorded In Other Assets FinancingReceivableRecordedInOtherAssets	131100000	USD
CY2020Q3	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	0.0	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	6300000	USD
	srt	Mortgage Loans On Real Estate Interest Rate MortgageLoansOnRealEstateInterestRate	0.0626
CY2020Q3	slg	Variable Interest Entity Not Primary Beneficiary Investment VariableInterestEntityNotPrimaryBeneficiaryInvestment	136300000	USD
CY2019Q4	slg	Variable Interest Entity Not Primary Beneficiary Investment VariableInterestEntityNotPrimaryBeneficiaryInvestment	145900000	USD
CY2020Q3	us-gaap	Equity Method Investment Difference Between Carrying Amount And Underlying Equity EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity	166800000	USD
CY2020Q3	us-gaap	Deferred Costs Leasing Gross DeferredCostsLeasingGross	496812000	USD
CY2019Q4	us-gaap	Deferred Costs Leasing Gross DeferredCostsLeasingGross	466136000	USD
CY2020Q3	slg	Accumulated Amortization Of Deferred Costs AccumulatedAmortizationOfDeferredCosts	290523000	USD
CY2019Q4	slg	Accumulated Amortization Of Deferred Costs AccumulatedAmortizationOfDeferredCosts	260853000	USD
CY2020Q3	us-gaap	Deferred Costs Current And Noncurrent DeferredCostsCurrentAndNoncurrent	206289000	USD
CY2020Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal Remainder Of Fiscal Year LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear	18158000	USD
CY2020Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	631240000	USD
CY2019Q4	us-gaap	Deferred Costs Current And Noncurrent DeferredCostsCurrentAndNoncurrent	205283000	USD
CY2020Q3	slg	Secured Debt Bearing Fixed Interest Amount SecuredDebtBearingFixedInterestAmount	1086141000	USD
CY2019Q4	slg	Secured Debt Bearing Fixed Interest Amount SecuredDebtBearingFixedInterestAmount	1383449000	USD
CY2020Q3	slg	Secured Debt Bearing Variable Interest Amount SecuredDebtBearingVariableInterestAmount	1338581000	USD
CY2019Q4	slg	Secured Debt Bearing Variable Interest Amount SecuredDebtBearingVariableInterestAmount	828434000	USD
CY2020Q3	slg	Secured Debt Gross SecuredDebtGross	2424722000	USD
CY2019Q4	slg	Secured Debt Gross SecuredDebtGross	2211883000	USD
CY2020Q3	slg	Secured Debt Deferred Finance Costs Net SecuredDebtDeferredFinanceCostsNet	32978000	USD
CY2019Q4	slg	Secured Debt Deferred Finance Costs Net SecuredDebtDeferredFinanceCostsNet	28630000	USD
CY2020Q3	us-gaap	Secured Debt SecuredDebt	2391744000	USD
CY2019Q4	us-gaap	Secured Debt SecuredDebt	2183253000	USD
CY2020Q3	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	3200000000	USD
CY2019Q4	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	3300000000	USD
CY2020Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	1064214000	USD
CY2020Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	2491542000	USD
CY2020Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	478043000	USD
CY2020Q3	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	781525000	USD
CY2020Q3	slg	Long Term Debt Maturities Repayments Of Principal LongTermDebtMaturitiesRepaymentsOfPrincipal	5464722000	USD
CY2020Q3	us-gaap	Interest Expense InterestExpense	42595000	USD
CY2019Q3	us-gaap	Interest Expense InterestExpense	63607000	USD
	us-gaap	Interest Expense InterestExpense	144345000	USD
	us-gaap	Interest Expense InterestExpense	185163000	USD
CY2020Q3	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	2198000	USD
CY2019Q3	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	813000	USD
	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	6010000	USD
	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	2425000	USD
CY2020Q3	us-gaap	Interest Costs Incurred Capitalized InterestCostsIncurredCapitalized	20677000	USD
CY2019Q3	us-gaap	Interest Costs Incurred Capitalized InterestCostsIncurredCapitalized	15700000	USD
	us-gaap	Interest Costs Incurred Capitalized InterestCostsIncurredCapitalized	57528000	USD
	us-gaap	Interest Costs Incurred Capitalized InterestCostsIncurredCapitalized	38228000	USD
CY2020Q3	us-gaap	Interest Income Operating InterestIncomeOperating	580000	USD
CY2019Q3	us-gaap	Interest Income Operating InterestIncomeOperating	608000	USD
	us-gaap	Interest Income Operating InterestIncomeOperating	1727000	USD
	us-gaap	Interest Income Operating InterestIncomeOperating	3563000	USD
CY2020Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-23536000	USD
CY2019Q3	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-48112000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-91100000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-145797000	USD
CY2020Q3	us-gaap	Due From Joint Ventures DueFromJointVentures	24912000	USD
CY2019Q4	us-gaap	Due From Joint Ventures DueFromJointVentures	9352000	USD
CY2020Q3	us-gaap	Due From Other Related Parties DueFromOtherRelatedParties	7024000	USD
CY2019Q4	us-gaap	Due From Other Related Parties DueFromOtherRelatedParties	11769000	USD
CY2020Q3	us-gaap	Due From Related Parties DueFromRelatedParties	31936000	USD
CY2019Q4	us-gaap	Due From Related Parties DueFromRelatedParties	21121000	USD
CY2020Q3	slg	Total Shares Authorized TotalSharesAuthorized	260000000	shares
CY2020Q3	slg	Total Par Or Stated Value Per Share TotalParOrStatedValuePerShare	0.01
CY2020Q3	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	160000000	shares
CY2020Q3	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2020Q3	us-gaap	Excess Stock Shares Authorized ExcessStockSharesAuthorized	75000000	shares
CY2020Q3	slg	Excess Stock Par Or Stated Value Per Share ExcessStockParOrStatedValuePerShare	0.01
CY2020Q3	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	25000000	shares
CY2020Q3	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2020Q3	us-gaap	Excess Stock Shares Issued ExcessStockSharesIssued	0	shares
CY2017	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	8342411	shares
CY2017	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	101.64
CY2018	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	9744911	shares
CY2018	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	96.22
CY2019	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	4596171	shares
CY2019	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	83.62
	us-gaap	Stock Repurchased During Period Shares StockRepurchasedDuringPeriodShares	6243165	shares
	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	62.77
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	13859000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	33157000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	185104000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	238052000	USD
CY2020Q3	us-gaap	Distributed Earnings DistributedEarnings	333000	USD
CY2019Q3	us-gaap	Distributed Earnings DistributedEarnings	108000	USD
	us-gaap	Distributed Earnings DistributedEarnings	777000	USD
	us-gaap	Distributed Earnings DistributedEarnings	325000	USD
CY2020Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	0	USD
CY2019Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	0	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	141000	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	41000	USD
CY2020Q3	slg	Net Income Loss Available To Common Stockholders After Distributed And Undistributed Earnings Allocation Basic NetIncomeLossAvailableToCommonStockholdersAfterDistributedAndUndistributedEarningsAllocationBasic	13526000	USD
CY2019Q3	slg	Net Income Loss Available To Common Stockholders After Distributed And Undistributed Earnings Allocation Basic NetIncomeLossAvailableToCommonStockholdersAfterDistributedAndUndistributedEarningsAllocationBasic	33049000	USD
	slg	Net Income Loss Available To Common Stockholders After Distributed And Undistributed Earnings Allocation Basic NetIncomeLossAvailableToCommonStockholdersAfterDistributedAndUndistributedEarningsAllocationBasic	184186000	USD
	slg	Net Income Loss Available To Common Stockholders After Distributed And Undistributed Earnings Allocation Basic NetIncomeLossAvailableToCommonStockholdersAfterDistributedAndUndistributedEarningsAllocationBasic	237686000	USD
CY2019Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	82292000	shares
CY2020Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	-333000	USD
CY2019Q3	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	-108000	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	-777000	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	-325000	USD
CY2020Q3	slg	Distributed Earnings Diluted DistributedEarningsDiluted	0	USD
CY2019Q3	slg	Distributed Earnings Diluted DistributedEarningsDiluted	0	USD
	slg	Distributed Earnings Diluted DistributedEarningsDiluted	-141000	USD
	slg	Distributed Earnings Diluted DistributedEarningsDiluted	-41000	USD
CY2020Q3	us-gaap	Dilutive Securities Effect On Basic Earnings Per Share Other DilutiveSecuritiesEffectOnBasicEarningsPerShareOther	802000	USD
CY2019Q3	us-gaap	Dilutive Securities Effect On Basic Earnings Per Share Other DilutiveSecuritiesEffectOnBasicEarningsPerShareOther	1719000	USD
	us-gaap	Dilutive Securities Effect On Basic Earnings Per Share Other DilutiveSecuritiesEffectOnBasicEarningsPerShareOther	10073000	USD
	us-gaap	Dilutive Securities Effect On Basic Earnings Per Share Other DilutiveSecuritiesEffectOnBasicEarningsPerShareOther	12306000	USD
CY2020Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	14661000	USD
CY2019Q3	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	34876000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	195177000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	250358000	USD
CY2020Q3	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	73020000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	75521000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	82855000	shares
CY2020Q3	slg	Incremental Common Shares Attributable To Redemption Of Units To Common Shares IncrementalCommonSharesAttributableToRedemptionOfUnitsToCommonShares	4029000	shares
CY2019Q3	slg	Incremental Common Shares Attributable To Redemption Of Units To Common Shares IncrementalCommonSharesAttributableToRedemptionOfUnitsToCommonShares	4258000	shares
	slg	Incremental Common Shares Attributable To Redemption Of Units To Common Shares IncrementalCommonSharesAttributableToRedemptionOfUnitsToCommonShares	4123000	shares
	slg	Incremental Common Shares Attributable To Redemption Of Units To Common Shares IncrementalCommonSharesAttributableToRedemptionOfUnitsToCommonShares	4283000	shares
CY2020Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	442000	shares
CY2019Q3	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	164000	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	441000	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	171000	shares
CY2020Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	77491000	shares
CY2019Q3	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	86714000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	80085000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	87309000	shares
CY2020Q3	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	2131606	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	1779212	shares
CY2020Q3	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	600000	USD
	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	1700000	USD
CY2019Q3	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	500000	USD
	us-gaap	Employee Service Share Based Compensation Allocation Of Recognized Period Costs Capitalized Amount EmployeeServiceShareBasedCompensationAllocationOfRecognizedPeriodCostsCapitalizedAmount	1400000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-60039000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	-12324000	USD
CY2020Q3	slg	Other Comprehensive Income Loss Deferred Net Lossfrom Terminated Hedges OtherComprehensiveIncomeLossDeferredNetLossfromTerminatedHedges	-500000	USD
CY2019Q4	slg	Other Comprehensive Income Loss Deferred Net Lossfrom Terminated Hedges OtherComprehensiveIncomeLossDeferredNetLossfromTerminatedHedges	-700000	USD
CY2020Q3	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	27734000	USD
CY2020Q3	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	39000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	29887000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	4419000	USD
CY2020Q3	slg	Accumulated Other Comprehensive Income Loss Gain Lossfrom Changesin Fair Value AccumulatedOtherComprehensiveIncomeLossGainLossfromChangesinFairValue	0	USD
CY2019Q3	slg	Accumulated Other Comprehensive Income Loss Gain Lossfrom Changesin Fair Value AccumulatedOtherComprehensiveIncomeLossGainLossfromChangesinFairValue	0	USD
	slg	Accumulated Other Comprehensive Income Loss Gain Lossfrom Changesin Fair Value AccumulatedOtherComprehensiveIncomeLossGainLossfromChangesinFairValue	0	USD
	slg	Accumulated Other Comprehensive Income Loss Gain Lossfrom Changesin Fair Value AccumulatedOtherComprehensiveIncomeLossGainLossfromChangesinFairValue	0	USD
CY2020Q3	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	68900000	USD
CY2020Q3	us-gaap	Assets Needed For Immediate Settlement Aggregate Fair Value AssetsNeededForImmediateSettlementAggregateFairValue	70200000	USD
	us-gaap	Cash Flow Hedge Gain Loss To Be Reclassified Within Twelve Months CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths	-17700000	USD
	slg	Cash Flow Hedge Gain Loss To Be Reclassified Within Twelve Months Into Equity In Net Income CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonthsIntoEquityInNetIncome	-7400000	USD
CY2020Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-517000	USD
CY2019Q3	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-12606000	USD
CY2020Q3	us-gaap	Interest Rate Cash Flow Hedge Gain Loss Reclassified To Earnings Net InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet	6616000	USD
CY2019Q3	us-gaap	Interest Rate Cash Flow Hedge Gain Loss Reclassified To Earnings Net InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet	297000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-61183000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-54971000	USD
	us-gaap	Interest Rate Cash Flow Hedge Gain Loss Reclassified To Earnings Net InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet	12957000	USD
	us-gaap	Interest Rate Cash Flow Hedge Gain Loss Reclassified To Earnings Net InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet	-1599000	USD
CY2020Q3	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	171866000	USD
CY2019Q3	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	214282000	USD
	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	538601000	USD
	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	641007000	USD
CY2020Q3	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	21979000	USD
CY2019Q3	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	32581000	USD
	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	70892000	USD
	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	88539000	USD
CY2020Q3	slg	Operating Lease Lease Income Fixed And Variable Lease Payments OperatingLeaseLeaseIncomeFixedAndVariableLeasePayments	193845000	USD
CY2019Q3	slg	Operating Lease Lease Income Fixed And Variable Lease Payments OperatingLeaseLeaseIncomeFixedAndVariableLeasePayments	246863000	USD
	slg	Operating Lease Lease Income Fixed And Variable Lease Payments OperatingLeaseLeaseIncomeFixedAndVariableLeasePayments	609493000	USD
	slg	Operating Lease Lease Income Fixed And Variable Lease Payments OperatingLeaseLeaseIncomeFixedAndVariableLeasePayments	729546000	USD
CY2020Q3	us-gaap	Amortization Of Above And Below Market Leases AmortizationOfAboveAndBelowMarketLeases	1670000	USD
CY2019Q3	us-gaap	Amortization Of Above And Below Market Leases AmortizationOfAboveAndBelowMarketLeases	1165000	USD
	us-gaap	Amortization Of Above And Below Market Leases AmortizationOfAboveAndBelowMarketLeases	4539000	USD
	us-gaap	Amortization Of Above And Below Market Leases AmortizationOfAboveAndBelowMarketLeases	3559000	USD
CY2020Q3	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	195515000	USD
CY2019Q3	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	248028000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	614032000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	733105000	USD
CY2020Q3	us-gaap	Sales Type Lease Selling Profit Loss SalesTypeLeaseSellingProfitLoss	-5973000	USD
CY2019Q3	us-gaap	Sales Type Lease Selling Profit Loss SalesTypeLeaseSellingProfitLoss	0	USD
	us-gaap	Sales Type Lease Selling Profit Loss SalesTypeLeaseSellingProfitLoss	-5973000	USD
	us-gaap	Sales Type Lease Selling Profit Loss SalesTypeLeaseSellingProfitLoss	0	USD
CY2020Q3	us-gaap	Sales Type Lease Interest Income SalesTypeLeaseInterestIncome	484000	USD
CY2019Q3	us-gaap	Sales Type Lease Interest Income SalesTypeLeaseInterestIncome	0	USD
	us-gaap	Sales Type Lease Interest Income SalesTypeLeaseInterestIncome	484000	USD
	us-gaap	Sales Type Lease Interest Income SalesTypeLeaseInterestIncome	0	USD
CY2020Q3	us-gaap	Sales Type Lease Lease Income SalesTypeLeaseLeaseIncome	-5489000	USD
CY2019Q3	us-gaap	Sales Type Lease Lease Income SalesTypeLeaseLeaseIncome	0	USD
	us-gaap	Sales Type Lease Lease Income SalesTypeLeaseLeaseIncome	-5489000	USD
	us-gaap	Sales Type Lease Lease Income SalesTypeLeaseLeaseIncome	0	USD
CY2020Q3	slg	Finance Lease Liability Payments Due After Year Six FinanceLeaseLiabilityPaymentsDueAfterYearSix	1018013000	USD
CY2020Q3	slg	Lessee Operating Lease Liability Payments Due After Year Six LesseeOperatingLeaseLiabilityPaymentsDueAfterYearSix	618326000	USD
CY2020Q3	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	1078945000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	756958000	USD
CY2020Q3	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	903962000	USD
	slg	Operating Leases Minimum Lease Term OperatingLeasesMinimumLeaseTerm	P1Y
CY2020Q3	us-gaap	Finance Lease Liability Payments Remainder Of Fiscal Year FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear	1974000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	7363000	USD
CY2020Q3	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	34885000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	29452000	USD
CY2020Q3	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	5881000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	27148000	USD
CY2020Q3	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	5927000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	24844000	USD
CY2020Q3	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	5999000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	24863000	USD
CY2020Q3	slg	Finance Lease Liability Payments Due Year Six FinanceLeaseLiabilityPaymentsDueYearSix	6266000	USD
CY2020Q3	slg	Lessee Operating Lease Liability Payments Due Year Six LesseeOperatingLeaseLiabilityPaymentsDueYearSix	24962000	USD
CY2020Q3	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	398539000	USD
CY2020Q3	us-gaap	Finance Lease Liability FinanceLeaseLiability	174983000	USD
CY2020Q3	us-gaap	Operating Lease Liability OperatingLeaseLiability	358419000	USD
CY2020Q3	us-gaap	Lessor Operating Lease Payments To Be Received LessorOperatingLeasePaymentsToBeReceived	1700000000	USD
CY2020Q3	slg	Operating Lease Cost Before Capitalized Operating Lease Costs OperatingLeaseCostBeforeCapitalizedOperatingLeaseCosts	7751000	USD
CY2019Q3	slg	Operating Lease Cost Before Capitalized Operating Lease Costs OperatingLeaseCostBeforeCapitalizedOperatingLeaseCosts	8315000	USD
	slg	Operating Lease Cost Before Capitalized Operating Lease Costs OperatingLeaseCostBeforeCapitalizedOperatingLeaseCosts	24486000	USD
	slg	Operating Lease Cost Before Capitalized Operating Lease Costs OperatingLeaseCostBeforeCapitalizedOperatingLeaseCosts	24918000	USD
CY2020Q3	slg	Operating Lease Cost Capitalized OperatingLeaseCostCapitalized	778000	USD
CY2019Q3	slg	Operating Lease Cost Capitalized OperatingLeaseCostCapitalized	20000	USD
	slg	Operating Lease Cost Capitalized OperatingLeaseCostCapitalized	2315000	USD
	slg	Operating Lease Cost Capitalized OperatingLeaseCostCapitalized	27000	USD
CY2020Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	6973000	USD
CY2019Q3	us-gaap	Operating Lease Cost OperatingLeaseCost	8295000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	22171000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	24891000	USD
CY2020Q3	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	2198000	USD
CY2019Q3	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	813000	USD
	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	6010000	USD
	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	2425000	USD
CY2020Q3	slg	Finance Lease Interest Expense Capitalized FinanceLeaseInterestExpenseCapitalized	588000	USD
CY2019Q3	slg	Finance Lease Interest Expense Capitalized FinanceLeaseInterestExpenseCapitalized	0	USD
	slg	Finance Lease Interest Expense Capitalized FinanceLeaseInterestExpenseCapitalized	2378000	USD
	slg	Finance Lease Interest Expense Capitalized FinanceLeaseInterestExpenseCapitalized	0	USD
CY2020Q3	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	1610000	USD
CY2019Q3	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	813000	USD
	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	3632000	USD
	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	2425000	USD
CY2020Q3	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	304000	USD
CY2019Q3	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	304000	USD
	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	914000	USD
	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	914000	USD
CY2020Q3	slg	Finance Lease Cost FinanceLeaseCost	1914000	USD
CY2019Q3	slg	Finance Lease Cost FinanceLeaseCost	1117000	USD
	slg	Finance Lease Cost FinanceLeaseCost	4546000	USD
	slg	Finance Lease Cost FinanceLeaseCost	3339000	USD
CY2020Q3	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0798
CY2020Q3	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P32Y
	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2	segment
CY2020Q3	us-gaap	Revenues Revenues	249844000	USD
CY2019Q3	us-gaap	Revenues Revenues	313634000	USD
	us-gaap	Revenues Revenues	817846000	USD
	us-gaap	Revenues Revenues	930913000	USD
CY2020Q3	slg	Income Loss From Continuing Operations Before Realized Gain Loss On Disposal Of Equity Method Investment IncomeLossFromContinuingOperationsBeforeRealizedGainLossOnDisposalOfEquityMethodInvestment	20677000	USD
CY2019Q3	slg	Income Loss From Continuing Operations Before Realized Gain Loss On Disposal Of Equity Method Investment IncomeLossFromContinuingOperationsBeforeRealizedGainLossOnDisposalOfEquityMethodInvestment	40722000	USD
	slg	Income Loss From Continuing Operations Before Realized Gain Loss On Disposal Of Equity Method Investment IncomeLossFromContinuingOperationsBeforeRealizedGainLossOnDisposalOfEquityMethodInvestment	214418000	USD
	slg	Income Loss From Continuing Operations Before Realized Gain Loss On Disposal Of Equity Method Investment IncomeLossFromContinuingOperationsBeforeRealizedGainLossOnDisposalOfEquityMethodInvestment	267232000	USD
CY2020Q3	us-gaap	Assets Assets	12324039000	USD
CY2019Q4	us-gaap	Assets Assets	12766320000	USD
CY2020Q3	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	23600000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	66700000	USD
CY2019Q3	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	23800000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	75300000	USD

Files In Submission

Name	View Source	Status
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$SLG
SL Green Realty Corp Stock $slg

2020 Q4 Form 10-Q Financial Statement

#000104097120000030 Filed on November 06, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$SLG SL Green Realty Corp Stock $slg

2020 Q4 Form 10-Q Financial Statement

#000104097120000030 Filed on November 06, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$SLG
SL Green Realty Corp Stock $slg