$SLG
SL GREEN REALTY CORP Stock $slg

$slg Overview Financials Valuation SEC Filings Company Website

2020 Q2 Form 10-Q Financial Statement

#000104097120000022 Filed on August 10, 2020

Income Statement

Concept	2020 Q2	2019 Q2	2019 Q1
Revenue	$253.7M	$313.0M	$304.3M
YoY Change	-18.95%	3.95%	0.85%
Cost Of Revenue	$90.40M	$113.3M	$112.7M
YoY Change	-20.21%	2.63%	-0.97%
Gross Profit	$163.3M	$199.7M	$191.6M
YoY Change	-18.23%	4.72%	1.97%
Gross Profit Margin	64.37%	63.8%	62.97%
Selling, General & Admin	$23.50M	$25.50M	$26.00M
YoY Change	-7.84%	13.33%	10.51%
% of Gross Profit	14.39%	12.77%	13.57%
Research & Development
YoY Change
% of Gross Profit
Depreciation & Amortization	$98.60M	$72.20M	$71.09M
YoY Change	36.57%	0.98%	-2.52%
% of Gross Profit	60.38%	36.15%	37.1%
Operating Expenses	$23.50M	$25.50M	$26.00M
YoY Change	-7.84%	13.33%	10.51%
Operating Profit	$139.8M	$174.2M	$165.6M
YoY Change	-19.75%	3.57%	0.75%
Interest Expense	$44.94M	$60.75M	$60.81M
YoY Change	-26.02%	-1.31%	12.34%
% of Operating Profit	32.14%	34.87%	36.72%
Other Income/Expense, Net
YoY Change
Pretax Income	$66.60M	$173.7M	$52.80M
YoY Change	-61.66%	305.72%	21.62%
Income Tax	$900.0K	$700.0K	$800.0K
% Of Pretax Income	1.35%	0.4%	1.52%
Net Earnings	$60.18M	$164.8M	$47.53M
YoY Change	-63.49%	53.64%	-54.95%
Net Earnings / Revenue	23.72%	52.66%	15.62%
Basic Earnings Per Share	$0.76	$1.94	$0.52
Diluted Earnings Per Share	$0.76	$1.94	$0.52
COMMON SHARES
Basic Shares Outstanding	73.54M shares	82.97M shares	83.31M shares
Diluted Shares Outstanding	78.07M shares	87.40M shares	87.81M shares

Balance Sheet

Concept	2020 Q2	2019 Q2	2019 Q1
SHORT-TERM ASSETS
Cash & Short-Term Investments	$1.043B	$179.0M	$173.7M
YoY Change	482.65%	-43.33%	-45.21%
Cash & Equivalents	$1.015B	$149.0M	$144.3M
Short-Term Investments	$27.35M	$29.98M	$29.41M
Other Short-Term Assets
YoY Change
Inventory	$50.00M
Prepaid Expenses
Receivables	$410.0M	$404.0M	$414.0M
Other Receivables	$0.00	$0.00	$0.00
Total Short-Term Assets	$1.475B	$553.0M	$558.0M
YoY Change	166.73%	-56.76%	-26.39%
LONG-TERM ASSETS
Property, Plant & Equipment	$6.804B	$7.333B	$6.782B
YoY Change	-7.21%	11.19%	-0.69%
Goodwill
YoY Change
Intangibles
YoY Change
Long-Term Investments	$2.953B	$2.937B	$3.055B
YoY Change	0.53%	-4.01%	0.68%
Other Assets	$304.0M	$313.0M	$363.0M
YoY Change	-2.88%	7.19%	27.37%
Total Long-Term Assets	$11.60B	$13.08B	$12.83B
YoY Change	-11.32%	5.16%	1.62%
TOTAL ASSETS
Total Short-Term Assets	$1.475B	$553.0M	$558.0M
Total Long-Term Assets	$11.60B	$13.08B	$12.83B
Total Assets	$13.07B	$13.63B	$13.39B
YoY Change	-4.1%	-0.61%	0.04%
SHORT-TERM LIABILITIES
YoY Change
Accounts Payable	$166.0M	$133.0M	$112.0M
YoY Change	24.81%	-5.67%	-15.15%
Accrued Expenses	$376.0M	$413.0M	$419.0M
YoY Change	-8.96%	1488.46%	1032.43%
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	$626.0M	$688.0M	$672.0M
YoY Change	-9.01%	119.11%	110.66%
LONG-TERM LIABILITIES
Long-Term Debt	$6.277B	$6.127B	$5.934B
YoY Change	2.45%	3.83%	8.58%
Other Long-Term Liabilities	$379.0M	$247.0M	$238.0M
YoY Change	53.44%	-47.33%	-15.6%
Total Long-Term Liabilities	$6.656B	$6.374B	$6.172B
YoY Change	4.42%	0.06%	7.4%
TOTAL LIABILITIES
Total Short-Term Liabilities	$626.0M	$688.0M	$672.0M
Total Long-Term Liabilities	$6.656B	$6.374B	$6.172B
Total Liabilities	$7.282B	$7.062B	$6.844B
YoY Change	3.11%	5.66%	12.83%
SHAREHOLDERS EQUITY
Retained Earnings	$1.082B	$1.288B	$1.210B
YoY Change	-16.03%	-11.62%	-23.57%
Common Stock	$748.0K	$835.0K	$843.0K
YoY Change	-10.42%	-3.8%	-6.54%
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	1.055M shares	1.055M shares	1.055M shares
Shareholders Equity	$5.120B	$5.810B	$5.798B
YoY Change
Total Liabilities & Shareholders Equity	$13.07B	$13.63B	$13.39B
YoY Change	-4.1%	-0.61%	0.04%

Cashflow Statement

Concept	2020 Q2	2019 Q2	2019 Q1
OPERATING ACTIVITIES
Net Income	$60.18M	$164.8M	$47.53M
YoY Change	-63.49%	53.64%	-54.95%
Depreciation, Depletion And Amortization	$98.60M	$72.20M	$71.09M
YoY Change	36.57%	0.98%	-2.52%
Cash From Operating Activities	$182.3M	$155.6M	$62.31M
YoY Change	17.16%	2.57%	-34.09%
INVESTING ACTIVITIES
Capital Expenditures	-$81.50M	-$315.9M	-$39.50M
YoY Change	-74.2%	491.57%	-25.33%
Acquisitions
YoY Change
Other Investing Activities	$614.8M	$141.3M	-$252.3M
YoY Change	335.1%	-205.06%	-149.58%
Cash From Investing Activities	$533.2M	-$174.6M	-$291.8M
YoY Change	-405.38%	-7.08%	-164.0%
FINANCING ACTIVITIES
Cash Dividend Paid			$77.40M
YoY Change			-5.3%
Common Stock Issuance & Retirement, Net			$34.24M
YoY Change			-91.05%
Debt Paid & Issued, Net
YoY Change
Cash From Financing Activities	-235.3M	-35.60M	$246.1M
YoY Change	560.96%	-193.68%	-158.28%
NET CHANGE
Cash From Operating Activities	182.3M	155.6M	$62.31M
Cash From Investing Activities	533.2M	-174.6M	-$291.8M
Cash From Financing Activities	-235.3M	-35.60M	$246.1M
Net Change In Cash	480.2M	-54.60M	$16.60M
YoY Change	-979.49%	-3133.33%	-87.06%
FREE CASH FLOW
Cash From Operating Activities	$182.3M	$155.6M	$62.31M
Capital Expenditures	-$81.50M	-$315.9M	-$39.50M
Free Cash Flow	$263.8M	$471.5M	$101.8M
YoY Change	-44.05%	129.89%	-30.95%

Facts In Submission

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	dei	Amendment Flag AmendmentFlag	false
	dei	Current Fiscal Year End Date CurrentFiscalYearEndDate	--12-31
	dei	Document Fiscal Period Focus DocumentFiscalPeriodFocus	Q2
	dei	Document Fiscal Year Focus DocumentFiscalYearFocus	2020
	dei	Entity Central Index Key EntityCentralIndexKey	0001040971
	dei	Entity Small Business EntitySmallBusiness	false
	slg	Accumulated Other Comprehensive Income Loss Gain Lossfrom Changesin Fair Value AccumulatedOtherComprehensiveIncomeLossGainLossfromChangesinFairValue	0	USD
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CY2019Q4	slg	Discount Of Structured Finance Investments DiscountOfStructuredFinanceInvestments	14562000	USD
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	us-gaap	Affiliate Costs AffiliateCosts	8116000	USD
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	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
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	dei	Document Type DocumentType	10-Q
	dei	Document Quarterly Report DocumentQuarterlyReport	true
	dei	Document Period End Date DocumentPeriodEndDate	2020-06-30
	dei	Document Transition Report DocumentTransitionReport	false
	dei	Entity File Number EntityFileNumber	1-13199
	dei	Entity Registrant Name EntityRegistrantName	SL GREEN REALTY CORP
	dei	Entity Incorporation State Country Code EntityIncorporationStateCountryCode	MD
	dei	Entity Tax Identification Number EntityTaxIdentificationNumber	13-3956775
	dei	Entity Address Postal Zip Code EntityAddressPostalZipCode	10170
	dei	City Area Code CityAreaCode	212
	dei	Local Phone Number LocalPhoneNumber	594-2700
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	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	5161000	USD
	us-gaap	Amortization Of Financing Costs AmortizationOfFinancingCosts	5454000	USD
CY2020Q2	us-gaap	Depreciation And Amortization DepreciationAndAmortization	95941000	USD
CY2019Q2	us-gaap	Depreciation And Amortization DepreciationAndAmortization	69461000	USD
	us-gaap	Depreciation And Amortization DepreciationAndAmortization	164220000	USD
	us-gaap	Depreciation And Amortization DepreciationAndAmortization	137804000	USD
CY2020Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	6813000	USD
CY2019Q2	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	0	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	18061000	USD
	us-gaap	Provision For Loan And Lease Losses ProvisionForLoanAndLeaseLosses	0	USD
CY2020Q2	slg	Transaction Related Costs TransactionRelatedCosts	373000	USD
CY2019Q2	slg	Transaction Related Costs TransactionRelatedCosts	261000	USD
	slg	Transaction Related Costs TransactionRelatedCosts	438000	USD
	slg	Transaction Related Costs TransactionRelatedCosts	316000	USD
CY2020Q2	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	23510000	USD
CY2019Q2	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	25480000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	43080000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	51459000	USD
CY2020Q2	slg	Total Costs And Expenses Including Nonoperating Income Expense TotalCostsAndExpensesIncludingNonoperatingIncomeExpense	249757000	USD
CY2019Q2	slg	Total Costs And Expenses Including Nonoperating Income Expense TotalCostsAndExpensesIncludingNonoperatingIncomeExpense	258383000	USD
	slg	Total Costs And Expenses Including Nonoperating Income Expense TotalCostsAndExpensesIncludingNonoperatingIncomeExpense	496768000	USD
	slg	Total Costs And Expenses Including Nonoperating Income Expense TotalCostsAndExpensesIncludingNonoperatingIncomeExpense	518711000	USD
CY2020Q2	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-2199000	USD
CY2019Q2	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-7546000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-15013000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-12780000	USD
CY2020Q2	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	0	USD
CY2019Q2	us-gaap	Equity Method Investment Realized Gain Loss On Disposal EquityMethodInvestmentRealizedGainLossOnDisposal	59015000	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
CY2020Q2	slg	Purchase Price Fair Value Adjustment Gross PurchasePriceFairValueAdjustmentGross	0	USD
CY2019Q2	slg	Purchase Price Fair Value Adjustment Gross PurchasePriceFairValueAdjustmentGross	67631000	USD
	slg	Purchase Price Fair Value Adjustment Gross PurchasePriceFairValueAdjustmentGross	0	USD
	slg	Purchase Price Fair Value Adjustment Gross PurchasePriceFairValueAdjustmentGross	65590000	USD
CY2020Q2	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	64884000	USD
CY2019Q2	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	0	USD
	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	137520000	USD
	us-gaap	Gain Loss On Sale Of Properties Net Of Applicable Income Taxes GainLossOnSaleOfPropertiesNetOfApplicableIncomeTaxes	-1049000	USD
CY2020Q2	us-gaap	Profit Loss ProfitLoss	66627000	USD
CY2019Q2	us-gaap	Profit Loss ProfitLoss	173741000	USD
	us-gaap	Profit Loss ProfitLoss	193741000	USD
	us-gaap	Profit Loss ProfitLoss	226510000	USD
CY2020Q2	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Redeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsRedeemable	3070000	USD
CY2019Q2	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Redeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsRedeemable	8310000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Redeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsRedeemable	9272000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Operating Partnerships Redeemable NoncontrollingInterestInNetIncomeLossOperatingPartnershipsRedeemable	10587000	USD
CY2020Q2	us-gaap	Noncontrolling Interest In Net Income Loss Other Noncontrolling Interests Redeemable NoncontrollingInterestInNetIncomeLossOtherNoncontrollingInterestsRedeemable	1023000	USD
CY2019Q2	us-gaap	Noncontrolling Interest In Net Income Loss Other Noncontrolling Interests Redeemable NoncontrollingInterestInNetIncomeLossOtherNoncontrollingInterestsRedeemable	-2138000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Other Noncontrolling Interests Redeemable NoncontrollingInterestInNetIncomeLossOtherNoncontrollingInterestsRedeemable	730000	USD
	us-gaap	Net Income Loss NetIncomeLoss	178720000	USD
	us-gaap	Dividends Preferred Stock DividendsPreferredStock	7475000	USD
	us-gaap	Net Income Loss NetIncomeLoss	212370000	USD
CY2020Q2	us-gaap	Dividends Preferred Stock DividendsPreferredStock	3737000	USD
CY2019Q2	us-gaap	Dividends Preferred Stock DividendsPreferredStock	3737000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Other Noncontrolling Interests Redeemable NoncontrollingInterestInNetIncomeLossOtherNoncontrollingInterestsRedeemable	-1900000	USD
CY2020Q2	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Redeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersRedeemable	2353000	USD
CY2019Q2	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Redeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersRedeemable	2729000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Redeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersRedeemable	5019000	USD
	us-gaap	Noncontrolling Interest In Net Income Loss Preferred Unit Holders Redeemable NoncontrollingInterestInNetIncomeLossPreferredUnitHoldersRedeemable	5453000	USD
CY2020Q2	us-gaap	Net Income Loss NetIncomeLoss	60181000	USD
CY2019Q2	us-gaap	Net Income Loss NetIncomeLoss	164840000	USD
	us-gaap	Dividends Preferred Stock DividendsPreferredStock	7475000	USD
CY2020Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	56444000	USD
CY2019Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	161103000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	171245000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	204895000	USD
CY2020Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	0.74
CY2019Q2	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	1.94
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.22
	us-gaap	Earnings Per Share Basic EarningsPerShareBasic	2.46
CY2020Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	0.74
CY2019Q2	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	1.94
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.22
	us-gaap	Earnings Per Share Diluted EarningsPerShareDiluted	2.46
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	75690000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	82971000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	76782000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	83141000	shares
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	80219000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	87398000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	81392000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	87606000	shares
CY2020Q2	us-gaap	Profit Loss ProfitLoss	66627000	USD
CY2019Q2	us-gaap	Profit Loss ProfitLoss	173741000	USD
	us-gaap	Profit Loss ProfitLoss	193741000	USD
	us-gaap	Profit Loss ProfitLoss	226510000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-3590000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-26220000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-54325000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss After Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossAfterReclassificationAndTax	-47105000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	148093000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	1992000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	572000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	-2542000	USD
	us-gaap	Other Comprehensive Income Unrealized Holding Gain Loss On Securities Arising During Period Net Of Tax OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodNetOfTax	1341000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-1598000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-25648000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-56867000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax OtherComprehensiveIncomeLossNetOfTax	-45764000	USD
CY2020Q2	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	65029000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	136874000	USD
	us-gaap	Comprehensive Income Net Of Tax Including Portion Attributable To Noncontrolling Interest ComprehensiveIncomeNetOfTaxIncludingPortionAttributableToNoncontrollingInterest	180746000	USD
CY2020Q2	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	6446000	USD
CY2019Q2	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	8901000	USD
	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	15021000	USD
	us-gaap	Net Income Loss Attributable To Noncontrolling Interest NetIncomeLossAttributableToNoncontrollingInterest	14140000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest	-95000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest	-1258000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest	-2981000	USD
	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Noncontrolling Interest OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToNoncontrollingInterest	-2261000	USD
CY2020Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	58678000	USD
CY2019Q2	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	140450000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	124834000	USD
	us-gaap	Comprehensive Income Net Of Tax ComprehensiveIncomeNetOfTax	168867000	USD
CY2019Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5517198000	USD
CY2020Q1	slg	Profit Loss Less Minority Interest In Net Income Loss Operating Partnerships ProfitLossLessMinorityInterestInNetIncomeLossOperatingPartnerships	118246000	USD
CY2020Q1	us-gaap	Minority Interest Decrease From Redemptions MinorityInterestDecreaseFromRedemptions	1536000	USD
CY2020Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-52383000	USD
CY2020Q1	us-gaap	Dividends Preferred Stock DividendsPreferredStock	3738000	USD
CY2020Q1	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	166000	USD
CY2020Q1	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	84000	USD
CY2020Q1	slg	Reallocationof Noncontrolling Interest In Operating Partnership Increase Decrease ReallocationofNoncontrollingInterestInOperatingPartnershipIncreaseDecrease	38529000	USD
CY2020Q1	slg	Deferred Compensation Plan And Stock Award Net DeferredCompensationPlanAndStockAwardNet	5502000	USD
CY2020Q1	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	219576000	USD
CY2020Q1	slg	Consolidation Of Joint Venture Interest ConsolidationOfJointVentureInterest	3814000	USD
CY2020Q1	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	492000	USD
CY2020Q1	us-gaap	Dividends Common Stock DividendsCommonStock	22665000	USD
CY2020Q1	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5343965000	USD
CY2020Q2	slg	Profit Loss Less Minority Interest In Net Income Loss Operating Partnerships ProfitLossLessMinorityInterestInNetIncomeLossOperatingPartnerships	61204000	USD
CY2020Q2	us-gaap	Minority Interest Decrease From Redemptions MinorityInterestDecreaseFromRedemptions	0	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-1503000	USD
CY2020Q2	us-gaap	Dividends Preferred Stock DividendsPreferredStock	3737000	USD
CY2020Q2	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	198000	USD
CY2020Q2	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	8660000	USD
CY2020Q2	slg	Reallocationof Noncontrolling Interest In Operating Partnership Increase Decrease ReallocationofNoncontrollingInterestInOperatingPartnershipIncreaseDecrease	-7385000	USD
CY2020Q2	slg	Deferred Compensation Plan And Stock Award Net DeferredCompensationPlanAndStockAwardNet	7991000	USD
CY2020Q2	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	141292000	USD
CY2020Q2	slg	Consolidation Of Joint Venture Interest ConsolidationOfJointVentureInterest	4372000	USD
CY2020Q2	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	104000	USD
CY2020Q2	us-gaap	Dividends Common Stock DividendsCommonStock	66607000	USD
CY2020Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5205762000	USD
CY2018Q4	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5947855000	USD
CY2019Q1	slg	Profit Loss Less Minority Interest In Net Income Loss Operating Partnerships ProfitLossLessMinorityInterestInNetIncomeLossOperatingPartnerships	47767000	USD
CY2019Q1	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-19113000	USD
CY2019Q1	us-gaap	Dividends Preferred Stock DividendsPreferredStock	3738000	USD
CY2019Q1	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	47000	USD
CY2019Q1	us-gaap	Stock Issued During Period Value Conversion Of Units StockIssuedDuringPeriodValueConversionOfUnits	446000	USD
CY2019Q1	slg	Reallocationof Noncontrolling Interest In Operating Partnership Increase Decrease ReallocationofNoncontrollingInterestInOperatingPartnershipIncreaseDecrease	-28932000	USD
CY2019Q1	slg	Deferred Compensation Plan And Stock Award Net DeferredCompensationPlanAndStockAwardNet	4835000	USD
CY2019Q1	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	34243000	USD
CY2019Q1	slg	Consolidation Of Joint Venture Interest ConsolidationOfJointVentureInterest	161000	USD
CY2019Q1	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	208000	USD
CY2019Q1	us-gaap	Dividends Common Stock DividendsCommonStock	70554000	USD
CY2019Q1	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5844323000	USD
CY2019Q2	slg	Profit Loss Less Minority Interest In Net Income Loss Operating Partnerships ProfitLossLessMinorityInterestInNetIncomeLossOperatingPartnerships	162702000	USD
CY2019Q2	us-gaap	Minority Interest Decrease From Redemptions MinorityInterestDecreaseFromRedemptions	25791000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Net Of Tax Portion Attributable To Parent OtherComprehensiveIncomeLossNetOfTaxPortionAttributableToParent	-24390000	USD
CY2019Q2	us-gaap	Dividends Preferred Stock DividendsPreferredStock	3737000	USD
CY2019Q2	us-gaap	Stock Issued During Period Value Dividend Reinvestment Plan StockIssuedDuringPeriodValueDividendReinvestmentPlan	216000	USD
CY2019Q2	slg	Reallocationof Noncontrolling Interest In Operating Partnership Increase Decrease ReallocationofNoncontrollingInterestInOperatingPartnershipIncreaseDecrease	14904000	USD
CY2019Q2	slg	Deferred Compensation Plan And Stock Award Net DeferredCompensationPlanAndStockAwardNet	5698000	USD
CY2019Q2	us-gaap	Treasury Stock Value Acquired Cost Method TreasuryStockValueAcquiredCostMethod	75070000	USD
CY2019Q2	slg	Consolidation Of Joint Venture Interest ConsolidationOfJointVentureInterest	50532000	USD
CY2019Q2	us-gaap	Minority Interest Decrease From Distributions To Noncontrolling Interest Holders MinorityInterestDecreaseFromDistributionsToNoncontrollingInterestHolders	63000	USD
CY2019Q2	us-gaap	Dividends Common Stock DividendsCommonStock	69823000	USD
CY2019Q2	us-gaap	Stockholders Equity Including Portion Attributable To Noncontrolling Interest StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest	5879501000	USD
	us-gaap	Profit Loss ProfitLoss	193741000	USD
	us-gaap	Profit Loss ProfitLoss	226510000	USD
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	169381000	USD
	us-gaap	Depreciation Depletion And Amortization DepreciationDepletionAndAmortization	143258000	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-15013000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	0	USD
	us-gaap	Income Loss From Equity Method Investments IncomeLossFromEquityMethodInvestments	-12780000	USD
	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	206000	USD
	us-gaap	Equity Method Investment Dividends Or Distributions EquityMethodInvestmentDividendsOrDistributions	566000	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	65590000	USD
	us-gaap	Gains Losses On Sales Of Investment Real Estate GainsLossesOnSalesOfInvestmentRealEstate	137520000	USD
	us-gaap	Gains Losses On Sales Of Investment Real Estate GainsLossesOnSalesOfInvestmentRealEstate	-1049000	USD
	us-gaap	Provision For Loan Lease And Other Losses ProvisionForLoanLeaseAndOtherLosses	18061000	USD
	us-gaap	Straight Line Rent StraightLineRent	-2577000	USD
	us-gaap	Straight Line Rent StraightLineRent	5674000	USD
	slg	Non Cash Lease Expense NonCashLeaseExpense	6547000	USD
	slg	Non Cash Lease Expense NonCashLeaseExpense	6798000	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-7648000	USD
	us-gaap	Other Noncash Income Expense OtherNoncashIncomeExpense	-3754000	USD
	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	57325000	USD
	us-gaap	Increase Decrease In Accounts Receivable IncreaseDecreaseInAccountsReceivable	1109000	USD
	us-gaap	Increase Decrease In Due From Related Parties Current IncreaseDecreaseInDueFromRelatedPartiesCurrent	-4395000	USD
	us-gaap	Increase Decrease In Due From Related Parties Current IncreaseDecreaseInDueFromRelatedPartiesCurrent	-4481000	USD
	us-gaap	Increase Decrease In Deferred Leasing Fees IncreaseDecreaseInDeferredLeasingFees	11143000	USD
	us-gaap	Increase Decrease In Deferred Leasing Fees IncreaseDecreaseInDeferredLeasingFees	32183000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	17363000	USD
	us-gaap	Increase Decrease In Other Operating Assets IncreaseDecreaseInOtherOperatingAssets	295000	USD
	slg	Increase Decrease In Accrued Liabilities And Other IncreaseDecreaseInAccruedLiabilitiesAndOther	39318000	USD
	slg	Increase Decrease In Accrued Liabilities And Other IncreaseDecreaseInAccruedLiabilitiesAndOther	5299000	USD
	us-gaap	Increase Decrease In Deferred Liabilities IncreaseDecreaseInDeferredLiabilities	-3503000	USD
	us-gaap	Increase Decrease In Deferred Liabilities IncreaseDecreaseInDeferredLiabilities	-427000	USD
	slg	Increase Decrease In Operating Lease Liability IncreaseDecreaseInOperatingLeaseLiability	-5728000	USD
	slg	Increase Decrease In Operating Lease Liability IncreaseDecreaseInOperatingLeaseLiability	-5121000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	224305000	USD
	us-gaap	Net Cash Provided By Used In Operating Activities NetCashProvidedByUsedInOperatingActivities	217915000	USD
	us-gaap	Payments To Acquire Commercial Real Estate PaymentsToAcquireCommercialRealEstate	86846000	USD
	us-gaap	Payments To Acquire Commercial Real Estate PaymentsToAcquireCommercialRealEstate	262343000	USD
	slg	Payments To Acquire Land Buildings And Improvements PaymentsToAcquireLandBuildingsAndImprovements	183297000	USD
	slg	Payments To Acquire Land Buildings And Improvements PaymentsToAcquireLandBuildingsAndImprovements	93013000	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	18318000	USD
	us-gaap	Payments To Acquire Equity Method Investments PaymentsToAcquireEquityMethodInvestments	97447000	USD
	slg	Proceeds From Equity Method Investment Dividends Or Distributions ProceedsFromEquityMethodInvestmentDividendsOrDistributions	76091000	USD
	slg	Proceeds From Equity Method Investment Dividends Or Distributions ProceedsFromEquityMethodInvestmentDividendsOrDistributions	45241000	USD
	us-gaap	Proceeds From Real Estate And Real Estate Joint Ventures ProceedsFromRealEstateAndRealEstateJointVentures	249820000	USD
	us-gaap	Proceeds From Real Estate And Real Estate Joint Ventures ProceedsFromRealEstateAndRealEstateJointVentures	138526000	USD
	slg	Payments For Proceeds From Other Investments PaymentsForProceedsFromOtherInvestments	7324000	USD
	slg	Payments For Proceeds From Other Investments PaymentsForProceedsFromOtherInvestments	1056000	USD
	us-gaap	Payments To Acquire Investments PaymentsToAcquireInvestments	265574000	USD
	us-gaap	Payments To Acquire Investments PaymentsToAcquireInvestments	523476000	USD
	slg	Repayments Or Redemption Of Debt And Preferred Equity Investments RepaymentsOrRedemptionOfDebtAndPreferredEquityInvestments	639267000	USD
	slg	Repayments Or Redemption Of Debt And Preferred Equity Investments RepaymentsOrRedemptionOfDebtAndPreferredEquityInvestments	327392000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	403819000	USD
	us-gaap	Net Cash Provided By Used In Investing Activities NetCashProvidedByUsedInInvestingActivities	-466404000	USD
	us-gaap	Proceeds From Issuance Of Secured Debt ProceedsFromIssuanceOfSecuredDebt	642196000	USD
	us-gaap	Proceeds From Issuance Of Secured Debt ProceedsFromIssuanceOfSecuredDebt	427352000	USD
	us-gaap	Repayments Of Secured Debt RepaymentsOfSecuredDebt	266795000	USD
	us-gaap	Repayments Of Secured Debt RepaymentsOfSecuredDebt	43630000	USD
	us-gaap	Proceeds From Other Debt ProceedsFromOtherDebt	1275000000	USD
	us-gaap	Proceeds From Other Debt ProceedsFromOtherDebt	940000000	USD
	us-gaap	Repayments Of Other Debt RepaymentsOfOtherDebt	815000000	USD
	us-gaap	Repayments Of Other Debt RepaymentsOfOtherDebt	770000000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	364000	USD
	us-gaap	Proceeds From Stock Options Exercised ProceedsFromStockOptionsExercised	263000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	352048000	USD
	us-gaap	Payments For Repurchase Of Common Stock PaymentsForRepurchaseOfCommonStock	109313000	USD
	us-gaap	Payments For Repurchase Of Redeemable Preferred Stock PaymentsForRepurchaseOfRedeemablePreferredStock	59800000	USD
	us-gaap	Payments For Repurchase Of Redeemable Preferred Stock PaymentsForRepurchaseOfRedeemablePreferredStock	15142000	USD
	slg	Payments For Repurchase Of Partnership Units PaymentsForRepurchaseOfPartnershipUnits	18066000	USD
	slg	Payments For Repurchase Of Partnership Units PaymentsForRepurchaseOfPartnershipUnits	15851000	USD
	slg	Distributions To Noncontrolling Interests Other Partnerships DistributionsToNoncontrollingInterestsOtherPartnerships	596000	USD
	slg	Distributions To Noncontrolling Interests Other Partnerships DistributionsToNoncontrollingInterestsOtherPartnerships	271000	USD
	slg	Proceeds From Noncontrolling Interests In Other Partnerships ProceedsFromNoncontrollingInterestsInOtherPartnerships	8186000	USD
	slg	Proceeds From Noncontrolling Interests In Other Partnerships ProceedsFromNoncontrollingInterestsInOtherPartnerships	2469000	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	5110000	USD
	slg	Distribution To Noncontrolling Interest Operating Partnership DistributionToNoncontrollingInterestOperatingPartnership	7353000	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	153474000	USD
	us-gaap	Payments Of Dividends PaymentsOfDividends	154460000	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	16510000	USD
	slg	Deferred Loan Costs And Capitalized Lease Obligation DeferredLoanCostsAndCapitalizedLeaseObligation	14624000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	330000	USD
	us-gaap	Finance Lease Principal Payments FinanceLeasePrincipalPayments	0	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	231729000	USD
	us-gaap	Net Cash Provided By Used In Financing Activities NetCashProvidedByUsedInFinancingActivities	210523000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	859853000	USD
	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents Period Increase Decrease Including Exchange Rate Effect CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalentsPeriodIncreaseDecreaseIncludingExchangeRateEffect	-37966000	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
CY2020Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	1101283000	USD
CY2019Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	241147000	USD
	us-gaap	Partners Capital Account Redemptions PartnersCapitalAccountRedemptions	8744000	USD
	us-gaap	Partners Capital Account Redemptions PartnersCapitalAccountRedemptions	446000	USD
	us-gaap	Transfer Of Investments TransferOfInvestments	119467000	USD
	us-gaap	Transfer Of Investments TransferOfInvestments	0	USD
	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	6653000	USD
	us-gaap	Capital Expenditures Incurred But Not Yet Paid CapitalExpendituresIncurredButNotYetPaid	9021000	USD
	slg	Operating Partnership Noncontrolling Interest Fair Value Adjustment OperatingPartnershipNoncontrollingInterestFairValueAdjustment	31144000	USD
	slg	Operating Partnership Noncontrolling Interest Fair Value Adjustment OperatingPartnershipNoncontrollingInterestFairValueAdjustment	43835000	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	49687000	USD
	slg	Transfer To Net Assets Held For Sale TransferToNetAssetsHeldForSale	0	USD
	slg	Transfer To Liabilities Related To Net Assets Held For Sale TransferToLiabilitiesRelatedToNetAssetsHeldForSale	38272000	USD
	slg	Transfer To Liabilities Related To Net Assets Held For Sale TransferToLiabilitiesRelatedToNetAssetsHeldForSale	0	USD
	slg	Removalof Fully Depreciated Real Estate Assets RemovalofFullyDepreciatedRealEstateAssets	534000	USD
	slg	Removalof Fully Depreciated Real Estate Assets RemovalofFullyDepreciatedRealEstateAssets	5728000	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	8820000	USD
	slg	Share Repurchases Payable ShareRepurchasesPayable	0	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	114974000	USD
	us-gaap	Right Of Use Asset Obtained In Exchange For Operating Lease Liability RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability	389120000	USD
CY2020Q2	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	1015348000	USD
CY2019Q2	us-gaap	Cash And Cash Equivalents At Carrying Value CashAndCashEquivalentsAtCarryingValue	148978000	USD
CY2020Q2	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	85935000	USD
CY2019Q2	us-gaap	Restricted Cash And Cash Equivalents RestrictedCashAndCashEquivalents	92169000	USD
CY2020Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	1101283000	USD
CY2019Q2	us-gaap	Cash Cash Equivalents Restricted Cash And Restricted Cash Equivalents CashCashEquivalentsRestrictedCashAndRestrictedCashEquivalents	241147000	USD
	us-gaap	Transfer Of Investments TransferOfInvestments	119467000	USD
	us-gaap	Transfer Of Investments TransferOfInvestments	0	USD
CY2020Q2	slg	Numberof Real Estate Buildings NumberofRealEstateBuildings	72	building
CY2020Q2	us-gaap	Area Of Real Estate Property AreaOfRealEstateProperty	29843409	sqft
CY2020Q2	slg	Real Estate Weighted Average Occupancy RealEstateWeightedAverageOccupancy	0.932
CY2020Q2	slg	Mortgage Loanson Real Estate Commercialand Consumer Net Including Debt Investments Other MortgageLoansonRealEstateCommercialandConsumerNetIncludingDebtInvestmentsOther	1300000000	USD
CY2020Q2	slg	Debt Investments Other DebtInvestmentsOther	100000000	USD
	slg	Number Of Shares On Redemption Of One Unit Of Partnership Interest NumberOfSharesOnRedemptionOfOneUnitOfPartnershipInterest	1	shares
CY2020Q2	slg	Rental Revenue Increase Decrease Acquired Lease Amortization RentalRevenueIncreaseDecreaseAcquiredLeaseAmortization	1600000	USD
	slg	Rental Revenue Increase Decrease Acquired Lease Amortization RentalRevenueIncreaseDecreaseAcquiredLeaseAmortization	2900000	USD
CY2019Q2	slg	Rental Revenue Increase Decrease Acquired Lease Amortization RentalRevenueIncreaseDecreaseAcquiredLeaseAmortization	1200000	USD
	slg	Rental Revenue Increase Decrease Acquired Lease Amortization RentalRevenueIncreaseDecreaseAcquiredLeaseAmortization	2400000	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	224411000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Gross FiniteLivedIntangibleAssetsGross	255198000	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	205314000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Accumulated Amortization FiniteLivedIntangibleAssetsAccumulatedAmortization	228223000	USD
CY2020Q2	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	19097000	USD
CY2019Q4	us-gaap	Finite Lived Intangible Assets Net FiniteLivedIntangibleAssetsNet	26975000	USD
CY2020Q2	slg	Finite Lived Intangible Liabilities Gross FiniteLivedIntangibleLiabilitiesGross	273240000	USD
CY2019Q4	slg	Finite Lived Intangible Liabilities Gross FiniteLivedIntangibleLiabilitiesGross	282048000	USD
CY2020Q2	slg	Finite Lived Intangible Liabilities Accumulated Amortization FiniteLivedIntangibleLiabilitiesAccumulatedAmortization	250912000	USD
CY2019Q4	slg	Finite Lived Intangible Liabilities Accumulated Amortization FiniteLivedIntangibleLiabilitiesAccumulatedAmortization	249514000	USD
CY2020Q2	slg	Finite Lived Intangible Liabilities Net FiniteLivedIntangibleLiabilitiesNet	22328000	USD
CY2019Q4	slg	Finite Lived Intangible Liabilities Net FiniteLivedIntangibleLiabilitiesNet	32534000	USD
CY2020Q2	slg	Net Intangible Assets Transferredto Assets Heldfor Sale NetIntangibleAssetsTransferredtoAssetsHeldforSale	0	USD
CY2020Q2	slg	Net Intangible Liabilities Transferredto Liabilities Relatedto Assets Heldfor Sale NetIntangibleLiabilitiesTransferredtoLiabilitiesRelatedtoAssetsHeldforSale	400000	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
CY2020Q2	us-gaap	Mortgage Loans On Real Estate Commercial And Consumer Net MortgageLoansOnRealEstateCommercialAndConsumerNet	1221936000	USD
CY2020Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	900000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	2000000.0	USD
CY2019Q2	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	700000	USD
	us-gaap	Income Tax Expense Benefit IncomeTaxExpenseBenefit	1500000	USD
	us-gaap	Use Of Estimates UseOfEstimates	<div style="line-height:120%;padding-bottom:8px;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;font-weight:bold;">Use of Estimates</span></div><div style="line-height:120%;padding-bottom:8px;text-align:justify;text-indent:32px;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">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="line-height:120%;padding-bottom:8px;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;font-weight:bold;">Concentrations of Credit Risk</span></div><div style="line-height:120%;padding-bottom:8px;text-align:justify;text-indent:32px;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">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="line-height:120%;padding-bottom:8px;text-align:justify;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;font-weight:bold;">Reclassification</span></div><div style="line-height:120%;padding-bottom:8px;text-align:justify;text-indent:32px;font-size:10pt;"><span style="font-family:inherit;font-size:10pt;">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	794959000	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	-13359000	USD
CY2019	slg	Sec Schedule1229 Real Estate Companies Investment In Mortgage Loans On Real Estate Loan Loss Reserve Period Increase Decrease SECSchedule1229RealEstateCompaniesInvestmentInMortgageLoansOnRealEstateLoanLossReservePeriodIncreaseDecrease	4000000	USD
CY2020Q2	us-gaap	Mortgage Loans On Real Estate MortgageLoansOnRealEstate	1221936000	USD
CY2019Q4	us-gaap	Mortgage Loans On Real Estate MortgageLoansOnRealEstate	1580306000	USD
CY2020Q2	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	11784000	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	26229000	USD
CY2019	slg	Financing Receivable Allowance For Credit Losses Write Offs And Reclassifications FinancingReceivableAllowanceForCreditLossesWriteOffsAndReclassifications	4000000	USD
CY2020Q2	us-gaap	Allowance For Loan And Lease Losses Real Estate AllowanceForLoanAndLeaseLossesRealEstate	15109000	USD
CY2019Q4	us-gaap	Allowance For Loan And Lease Losses Real Estate AllowanceForLoanAndLeaseLossesRealEstate	1750000	USD
CY2020Q2	us-gaap	Financing Receivable Recorded Investment Nonaccrual Status FinancingReceivableRecordedInvestmentNonaccrualStatus	27700000	USD
CY2020Q2	slg	Debt And Equity Securities Weighted Average Risk Rating DebtAndEquitySecuritiesWeightedAverageRiskRating	1.4
	slg	Financing Receivable Portfolio Segments Number FinancingReceivablePortfolioSegmentsNumber	1	segment
CY2020Q2	slg	Financing Receivable Recorded In Other Assets FinancingReceivableRecordedInOtherAssets	118800000	USD
CY2019Q4	slg	Financing Receivable Recorded In Other Assets FinancingReceivableRecordedInOtherAssets	131100000	USD
CY2020Q2	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	3400000	USD
	us-gaap	Provision For Loan Losses Expensed ProvisionForLoanLossesExpensed	6300000	USD
	srt	Mortgage Loans On Real Estate Interest Rate MortgageLoansOnRealEstateInterestRate	0.0828
CY2020Q2	slg	Variable Interest Entity Not Primary Beneficiary Investment VariableInterestEntityNotPrimaryBeneficiaryInvestment	138100000	USD
CY2019Q4	slg	Variable Interest Entity Not Primary Beneficiary Investment VariableInterestEntityNotPrimaryBeneficiaryInvestment	145900000	USD
CY2020Q2	us-gaap	Equity Method Investment Difference Between Carrying Amount And Underlying Equity EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity	122600000	USD
CY2020Q2	us-gaap	Deferred Costs Leasing Gross DeferredCostsLeasingGross	502373000	USD
CY2019Q4	us-gaap	Deferred Costs Leasing Gross DeferredCostsLeasingGross	466136000	USD
CY2020Q2	slg	Accumulated Amortization Of Deferred Costs AccumulatedAmortizationOfDeferredCosts	284561000	USD
CY2019Q4	slg	Accumulated Amortization Of Deferred Costs AccumulatedAmortizationOfDeferredCosts	260853000	USD
CY2020Q2	us-gaap	Deferred Costs Current And Noncurrent DeferredCostsCurrentAndNoncurrent	217812000	USD
CY2019Q4	us-gaap	Deferred Costs Current And Noncurrent DeferredCostsCurrentAndNoncurrent	205283000	USD
CY2020Q2	slg	Secured Debt Bearing Fixed Interest Amount SecuredDebtBearingFixedInterestAmount	1127377000	USD
CY2019Q4	slg	Secured Debt Bearing Fixed Interest Amount SecuredDebtBearingFixedInterestAmount	1383449000	USD
CY2020Q2	slg	Secured Debt Bearing Variable Interest Amount SecuredDebtBearingVariableInterestAmount	1259915000	USD
CY2019Q4	slg	Secured Debt Bearing Variable Interest Amount SecuredDebtBearingVariableInterestAmount	828434000	USD
CY2020Q2	slg	Secured Debt And Other Loans Payable SecuredDebtAndOtherLoansPayable	2387292000	USD
CY2019Q4	slg	Secured Debt And Other Loans Payable SecuredDebtAndOtherLoansPayable	2211883000	USD
CY2020Q2	slg	Secured Debt Amount Transferredto Liabilities Relatedto Net Assets Heldfor Sale SecuredDebtAmountTransferredtoLiabilitiesRelatedtoNetAssetsHeldforSale	38809000	USD
CY2019Q4	slg	Secured Debt Amount Transferredto Liabilities Relatedto Net Assets Heldfor Sale SecuredDebtAmountTransferredtoLiabilitiesRelatedtoNetAssetsHeldforSale	0	USD
CY2020Q2	slg	Secured Debt Gross SecuredDebtGross	2348483000	USD
CY2019Q4	slg	Secured Debt Gross SecuredDebtGross	2211883000	USD
CY2020Q2	slg	Secured Debt Deferred Finance Costs Net SecuredDebtDeferredFinanceCostsNet	32079000	USD
CY2019Q4	slg	Secured Debt Deferred Finance Costs Net SecuredDebtDeferredFinanceCostsNet	28630000	USD
CY2020Q2	us-gaap	Secured Debt SecuredDebt	2316404000	USD
CY2019Q4	us-gaap	Secured Debt SecuredDebt	2183253000	USD
CY2020Q2	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	3200000000	USD
CY2019Q4	us-gaap	Collateral Already Posted Aggregate Fair Value CollateralAlreadyPostedAggregateFairValue	3300000000	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal Remainder Of Fiscal Year LongTermDebtMaturitiesRepaymentsOfPrincipalRemainderOfFiscalYear	46138000	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Two LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo	600513000	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Three LongTermDebtMaturitiesRepaymentsOfPrincipalInYearThree	1427712000	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Four LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFour	2817288000	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal In Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalInYearFive	478768000	USD
CY2020Q2	us-gaap	Long Term Debt Maturities Repayments Of Principal After Year Five LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive	816873000	USD
CY2020Q2	slg	Long Term Debt Maturities Repayments Of Principal LongTermDebtMaturitiesRepaymentsOfPrincipal	6187292000	USD
CY2020Q2	us-gaap	Interest Expense InterestExpense	44937000	USD
CY2019Q2	us-gaap	Interest Expense InterestExpense	60745000	USD
	us-gaap	Interest Expense InterestExpense	101751000	USD
	us-gaap	Interest Expense InterestExpense	121555000	USD
CY2020Q2	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	2149000	USD
CY2019Q2	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	808000	USD
	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	3812000	USD
	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	1612000	USD
CY2020Q2	us-gaap	Interest Costs Incurred Capitalized InterestCostsIncurredCapitalized	16368000	USD
CY2019Q2	us-gaap	Interest Costs Incurred Capitalized InterestCostsIncurredCapitalized	12019000	USD
	us-gaap	Interest Costs Incurred Capitalized InterestCostsIncurredCapitalized	36852000	USD
	us-gaap	Interest Costs Incurred Capitalized InterestCostsIncurredCapitalized	22528000	USD
CY2020Q2	us-gaap	Interest Income Operating InterestIncomeOperating	648000	USD
CY2019Q2	us-gaap	Interest Income Operating InterestIncomeOperating	2374000	USD
	us-gaap	Interest Income Operating InterestIncomeOperating	1147000	USD
	us-gaap	Interest Income Operating InterestIncomeOperating	2954000	USD
CY2020Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-30070000	USD
CY2019Q2	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-47160000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-67564000	USD
	us-gaap	Interest Income Expense Net InterestIncomeExpenseNet	-97685000	USD
CY2020Q2	us-gaap	Due From Joint Ventures DueFromJointVentures	9975000	USD
CY2019Q4	us-gaap	Due From Joint Ventures DueFromJointVentures	9352000	USD
CY2020Q2	us-gaap	Due From Other Related Parties DueFromOtherRelatedParties	7009000	USD
CY2019Q4	us-gaap	Due From Other Related Parties DueFromOtherRelatedParties	11769000	USD
CY2020Q2	us-gaap	Due From Related Parties DueFromRelatedParties	16984000	USD
CY2019Q4	us-gaap	Due From Related Parties DueFromRelatedParties	21121000	USD
CY2020Q2	slg	Total Shares Authorized TotalSharesAuthorized	260000000	shares
CY2020Q2	slg	Total Par Or Stated Value Per Share TotalParOrStatedValuePerShare	0.01
CY2020Q2	us-gaap	Common Stock Shares Authorized CommonStockSharesAuthorized	160000000	shares
CY2020Q2	us-gaap	Common Stock Par Or Stated Value Per Share CommonStockParOrStatedValuePerShare	0.01
CY2020Q2	us-gaap	Excess Stock Shares Authorized ExcessStockSharesAuthorized	75000000	shares
CY2020Q2	slg	Excess Stock Par Or Stated Value Per Share ExcessStockParOrStatedValuePerShare	0.01
CY2020Q2	us-gaap	Preferred Stock Shares Authorized PreferredStockSharesAuthorized	25000000	shares
CY2020Q2	us-gaap	Preferred Stock Par Or Stated Value Per Share PreferredStockParOrStatedValuePerShare	0.01
CY2020Q2	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	5600670	shares
	us-gaap	Treasury Stock Acquired Average Cost Per Share TreasuryStockAcquiredAverageCostPerShare	64.42
CY2020Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	56444000	USD
CY2019Q2	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	161103000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	171245000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Basic NetIncomeLossAvailableToCommonStockholdersBasic	204895000	USD
CY2020Q2	us-gaap	Distributed Earnings DistributedEarnings	333000	USD
CY2019Q2	us-gaap	Distributed Earnings DistributedEarnings	128000	USD
	us-gaap	Distributed Earnings DistributedEarnings	444000	USD
	us-gaap	Distributed Earnings DistributedEarnings	257000	USD
CY2020Q2	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	0	USD
CY2019Q2	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	164000	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	391000	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Basic UndistributedEarningsLossAllocatedToParticipatingSecuritiesBasic	115000	USD
CY2020Q2	slg	Net Income Loss Available To Common Stockholders After Distributed And Undistributed Earnings Allocation Basic NetIncomeLossAvailableToCommonStockholdersAfterDistributedAndUndistributedEarningsAllocationBasic	56111000	USD
CY2019Q2	slg	Net Income Loss Available To Common Stockholders After Distributed And Undistributed Earnings Allocation Basic NetIncomeLossAvailableToCommonStockholdersAfterDistributedAndUndistributedEarningsAllocationBasic	160811000	USD
	slg	Net Income Loss Available To Common Stockholders After Distributed And Undistributed Earnings Allocation Basic NetIncomeLossAvailableToCommonStockholdersAfterDistributedAndUndistributedEarningsAllocationBasic	170410000	USD
	slg	Net Income Loss Available To Common Stockholders After Distributed And Undistributed Earnings Allocation Basic NetIncomeLossAvailableToCommonStockholdersAfterDistributedAndUndistributedEarningsAllocationBasic	204523000	USD
CY2020Q2	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	-333000	USD
CY2019Q2	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	-128000	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	-444000	USD
	us-gaap	Undistributed Earnings Loss Allocated To Participating Securities Diluted UndistributedEarningsLossAllocatedToParticipatingSecuritiesDiluted	-257000	USD
CY2020Q2	slg	Distributed Earnings Diluted DistributedEarningsDiluted	0	USD
CY2019Q2	slg	Distributed Earnings Diluted DistributedEarningsDiluted	-164000	USD
	slg	Distributed Earnings Diluted DistributedEarningsDiluted	-391000	USD
	slg	Distributed Earnings Diluted DistributedEarningsDiluted	-115000	USD
CY2020Q2	us-gaap	Dilutive Securities Effect On Basic Earnings Per Share Other DilutiveSecuritiesEffectOnBasicEarningsPerShareOther	3070000	USD
CY2019Q2	us-gaap	Dilutive Securities Effect On Basic Earnings Per Share Other DilutiveSecuritiesEffectOnBasicEarningsPerShareOther	8310000	USD
	us-gaap	Dilutive Securities Effect On Basic Earnings Per Share Other DilutiveSecuritiesEffectOnBasicEarningsPerShareOther	9272000	USD
	us-gaap	Dilutive Securities Effect On Basic Earnings Per Share Other DilutiveSecuritiesEffectOnBasicEarningsPerShareOther	10587000	USD
CY2020Q2	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	59514000	USD
CY2019Q2	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	169413000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	180517000	USD
	us-gaap	Net Income Loss Available To Common Stockholders Diluted NetIncomeLossAvailableToCommonStockholdersDiluted	215482000	USD
CY2020Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	75690000	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	169000	shares
CY2020Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	80219000	shares
CY2019Q2	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	87398000	shares
	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	1643616	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	81392000	shares
	us-gaap	Weighted Average Number Of Diluted Shares Outstanding WeightedAverageNumberOfDilutedSharesOutstanding	87606000	shares
CY2020Q2	us-gaap	Antidilutive Securities Excluded From Computation Of Earnings Per Share Amount AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount	2192240	shares
CY2019Q2	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	82971000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	76782000	shares
	us-gaap	Weighted Average Number Of Shares Outstanding Basic WeightedAverageNumberOfSharesOutstandingBasic	83141000	shares
CY2020Q2	slg	Incremental Common Shares Attributable To Redemption Of Units To Common Shares IncrementalCommonSharesAttributableToRedemptionOfUnitsToCommonShares	4120000	shares
CY2019Q2	slg	Incremental Common Shares Attributable To Redemption Of Units To Common Shares IncrementalCommonSharesAttributableToRedemptionOfUnitsToCommonShares	4260000	shares
	slg	Incremental Common Shares Attributable To Redemption Of Units To Common Shares IncrementalCommonSharesAttributableToRedemptionOfUnitsToCommonShares	4170000	shares
	slg	Incremental Common Shares Attributable To Redemption Of Units To Common Shares IncrementalCommonSharesAttributableToRedemptionOfUnitsToCommonShares	4296000	shares
CY2020Q2	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	409000	shares
CY2019Q2	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	167000	shares
	us-gaap	Incremental Common Shares Attributable To Share Based Payment Arrangements IncrementalCommonSharesAttributableToShareBasedPaymentArrangements	440000	shares
CY2020Q2	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	1100000	USD
CY2019Q2	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	900000	USD
CY2019Q4	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	4419000	USD
	us-gaap	Other Comprehensive Income Loss Before Reclassifications Net Of Tax OtherComprehensiveIncomeLossBeforeReclassificationsNetOfTax	-59915000	USD
	us-gaap	Reclassification From Accumulated Other Comprehensive Income Current Period Net Of Tax ReclassificationFromAccumulatedOtherComprehensiveIncomeCurrentPeriodNetOfTax	-6029000	USD
CY2020Q2	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
CY2020Q2	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	27345000	USD
CY2020Q2	us-gaap	Derivative Fair Value Of Derivative Asset DerivativeFairValueOfDerivativeAsset	81000	USD
CY2019Q4	us-gaap	Available For Sale Securities Debt Securities AvailableForSaleSecuritiesDebtSecurities	29887000	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
CY2020Q2	us-gaap	Derivative Net Liability Position Aggregate Fair Value DerivativeNetLiabilityPositionAggregateFairValue	73600000	USD
CY2020Q2	us-gaap	Assets Needed For Immediate Settlement Aggregate Fair Value AssetsNeededForImmediateSettlementAggregateFairValue	75000000.0	USD
	us-gaap	Cash Flow Hedge Gain Loss To Be Reclassified Within Twelve Months CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths	-18600000	USD
	slg	Cash Flow Hedge Gain Loss To Be Reclassified Within Twelve Months Into Equity In Net Income CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonthsIntoEquityInNetIncome	-6600000	USD
CY2020Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-8494000	USD
CY2019Q2	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-25033000	USD
CY2020Q2	us-gaap	Interest Rate Cash Flow Hedge Gain Loss Reclassified To Earnings Net InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet	4904000	USD
CY2019Q2	us-gaap	Interest Rate Cash Flow Hedge Gain Loss Reclassified To Earnings Net InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet	-992000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-60664000	USD
	us-gaap	Other Comprehensive Income Loss Cash Flow Hedge Gain Loss Before Reclassification And Tax OtherComprehensiveIncomeLossCashFlowHedgeGainLossBeforeReclassificationAndTax	-42365000	USD
	us-gaap	Interest Rate Cash Flow Hedge Gain Loss Reclassified To Earnings Net InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet	6340000	USD
	us-gaap	Interest Rate Cash Flow Hedge Gain Loss Reclassified To Earnings Net InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet	-1896000	USD
CY2019Q2	slg	Operating Lease Cost Before Capitalized Operating Lease Costs OperatingLeaseCostBeforeCapitalizedOperatingLeaseCosts	8305000	USD
CY2020Q2	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	172511000	USD
CY2019Q2	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	215295000	USD
	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	366735000	USD
	us-gaap	Operating Lease Lease Income Lease Payments OperatingLeaseLeaseIncomeLeasePayments	426725000	USD
CY2020Q2	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	21745000	USD
CY2019Q2	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	28479000	USD
	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	48913000	USD
	us-gaap	Operating Lease Variable Lease Income OperatingLeaseVariableLeaseIncome	55958000	USD
CY2020Q2	slg	Operating Lease Lease Income Fixed And Variable Lease Payments OperatingLeaseLeaseIncomeFixedAndVariableLeasePayments	194256000	USD
CY2019Q2	slg	Operating Lease Lease Income Fixed And Variable Lease Payments OperatingLeaseLeaseIncomeFixedAndVariableLeasePayments	243774000	USD
	slg	Operating Lease Lease Income Fixed And Variable Lease Payments OperatingLeaseLeaseIncomeFixedAndVariableLeasePayments	415648000	USD
	slg	Operating Lease Lease Income Fixed And Variable Lease Payments OperatingLeaseLeaseIncomeFixedAndVariableLeasePayments	482683000	USD
CY2020Q2	us-gaap	Amortization Of Above And Below Market Leases AmortizationOfAboveAndBelowMarketLeases	1630000	USD
CY2019Q2	us-gaap	Amortization Of Above And Below Market Leases AmortizationOfAboveAndBelowMarketLeases	1185000	USD
	us-gaap	Amortization Of Above And Below Market Leases AmortizationOfAboveAndBelowMarketLeases	2869000	USD
	us-gaap	Amortization Of Above And Below Market Leases AmortizationOfAboveAndBelowMarketLeases	2394000	USD
CY2020Q2	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	195886000	USD
CY2019Q2	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	244959000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	418517000	USD
	us-gaap	Operating Lease Lease Income OperatingLeaseLeaseIncome	485077000	USD
CY2020Q2	us-gaap	Finance Lease Liability Payments Due Year Four FinanceLeaseLiabilityPaymentsDueYearFour	5927000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Remainder Of Fiscal Year LesseeOperatingLeaseLiabilityPaymentsRemainderOfFiscalYear	14721000	USD
CY2020Q2	us-gaap	Finance Lease Liability Payments Due Year Two FinanceLeaseLiabilityPaymentsDueYearTwo	34885000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Two LesseeOperatingLeaseLiabilityPaymentsDueYearTwo	29452000	USD
CY2020Q2	us-gaap	Finance Lease Liability Payments Due Year Three FinanceLeaseLiabilityPaymentsDueYearThree	5881000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Three LesseeOperatingLeaseLiabilityPaymentsDueYearThree	27148000	USD
	slg	Operating Leases Minimum Lease Term OperatingLeasesMinimumLeaseTerm	P1Y
CY2020Q2	us-gaap	Finance Lease Liability Payments Remainder Of Fiscal Year FinanceLeaseLiabilityPaymentsRemainderOfFiscalYear	3904000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Four LesseeOperatingLeaseLiabilityPaymentsDueYearFour	24844000	USD
CY2020Q2	us-gaap	Finance Lease Liability Payments Due Year Five FinanceLeaseLiabilityPaymentsDueYearFive	5999000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due Year Five LesseeOperatingLeaseLiabilityPaymentsDueYearFive	24863000	USD
CY2020Q2	slg	Finance Lease Liability Payments Due Year Six FinanceLeaseLiabilityPaymentsDueYearSix	6266000	USD
CY2020Q2	slg	Lessee Operating Lease Liability Payments Due Year Six LesseeOperatingLeaseLiabilityPaymentsDueYearSix	24962000	USD
CY2020Q2	slg	Finance Lease Liability Payments Due After Year Six FinanceLeaseLiabilityPaymentsDueAfterYearSix	1018013000	USD
CY2020Q2	slg	Lessee Operating Lease Liability Payments Due After Year Six LesseeOperatingLeaseLiabilityPaymentsDueAfterYearSix	618326000	USD
CY2020Q2	us-gaap	Finance Lease Liability Payments Due FinanceLeaseLiabilityPaymentsDue	1080875000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Payments Due LesseeOperatingLeaseLiabilityPaymentsDue	764316000	USD
CY2020Q2	us-gaap	Finance Lease Liability Undiscounted Excess Amount FinanceLeaseLiabilityUndiscountedExcessAmount	906143000	USD
CY2020Q2	us-gaap	Lessee Operating Lease Liability Undiscounted Excess Amount LesseeOperatingLeaseLiabilityUndiscountedExcessAmount	403095000	USD
CY2020Q2	us-gaap	Finance Lease Liability FinanceLeaseLiability	174732000	USD
CY2020Q2	us-gaap	Operating Lease Liability OperatingLeaseLiability	361221000	USD
CY2020Q2	us-gaap	Lessor Operating Lease Payments To Be Received LessorOperatingLeasePaymentsToBeReceived	1600000000	USD
CY2020Q2	slg	Operating Lease Cost Before Capitalized Operating Lease Costs OperatingLeaseCostBeforeCapitalizedOperatingLeaseCosts	8622000	USD
CY2019Q2	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	808000	USD
	slg	Operating Lease Cost Before Capitalized Operating Lease Costs OperatingLeaseCostBeforeCapitalizedOperatingLeaseCosts	16735000	USD
	slg	Operating Lease Cost Before Capitalized Operating Lease Costs OperatingLeaseCostBeforeCapitalizedOperatingLeaseCosts	16603000	USD
CY2020Q2	slg	Operating Lease Cost Capitalized OperatingLeaseCostCapitalized	791000	USD
CY2019Q2	slg	Operating Lease Cost Capitalized OperatingLeaseCostCapitalized	7000	USD
	slg	Operating Lease Cost Capitalized OperatingLeaseCostCapitalized	1537000	USD
	slg	Operating Lease Cost Capitalized OperatingLeaseCostCapitalized	7000	USD
CY2020Q2	us-gaap	Operating Lease Cost OperatingLeaseCost	7831000	USD
CY2019Q2	us-gaap	Operating Lease Cost OperatingLeaseCost	8298000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	15198000	USD
	us-gaap	Operating Lease Cost OperatingLeaseCost	16596000	USD
CY2020Q2	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	2149000	USD
CY2019Q2	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	808000	USD
	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	3812000	USD
	slg	Finance Lease Interest Expense Before Capitalized Interest FinanceLeaseInterestExpenseBeforeCapitalizedInterest	1612000	USD
CY2020Q2	slg	Finance Lease Interest Expense Capitalized FinanceLeaseInterestExpenseCapitalized	1043000	USD
CY2019Q2	slg	Finance Lease Interest Expense Capitalized FinanceLeaseInterestExpenseCapitalized	0	USD
	slg	Finance Lease Interest Expense Capitalized FinanceLeaseInterestExpenseCapitalized	1790000	USD
	slg	Finance Lease Interest Expense Capitalized FinanceLeaseInterestExpenseCapitalized	0	USD
CY2020Q2	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	1106000	USD
	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	2022000	USD
	us-gaap	Finance Lease Interest Expense FinanceLeaseInterestExpense	1612000	USD
CY2020Q2	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	305000	USD
CY2019Q2	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	305000	USD
	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	610000	USD
	us-gaap	Finance Lease Right Of Use Asset Amortization FinanceLeaseRightOfUseAssetAmortization	610000	USD
CY2020Q2	slg	Finance Lease Cost FinanceLeaseCost	1411000	USD
CY2019Q2	slg	Finance Lease Cost FinanceLeaseCost	1113000	USD
	slg	Finance Lease Cost FinanceLeaseCost	2632000	USD
	slg	Finance Lease Cost FinanceLeaseCost	2222000	USD
CY2020Q2	us-gaap	Operating Lease Weighted Average Discount Rate Percent OperatingLeaseWeightedAverageDiscountRatePercent	0.0797
CY2020Q2	us-gaap	Operating Lease Weighted Average Remaining Lease Term1 OperatingLeaseWeightedAverageRemainingLeaseTerm1	P32Y
	us-gaap	Number Of Reportable Segments NumberOfReportableSegments	2	segment
CY2020Q2	us-gaap	Revenues Revenues	253699000	USD
CY2019Q2	us-gaap	Revenues Revenues	313024000	USD
	us-gaap	Revenues Revenues	568002000	USD
	us-gaap	Revenues Revenues	617279000	USD
CY2020Q2	slg	Income Loss From Continuing Operations Before Realized Gain Loss On Disposal Of Equity Method Investment IncomeLossFromContinuingOperationsBeforeRealizedGainLossOnDisposalOfEquityMethodInvestment	66627000	USD
CY2019Q2	slg	Income Loss From Continuing Operations Before Realized Gain Loss On Disposal Of Equity Method Investment IncomeLossFromContinuingOperationsBeforeRealizedGainLossOnDisposalOfEquityMethodInvestment	173741000	USD
	slg	Income Loss From Continuing Operations Before Realized Gain Loss On Disposal Of Equity Method Investment IncomeLossFromContinuingOperationsBeforeRealizedGainLossOnDisposalOfEquityMethodInvestment	193741000	USD
	slg	Income Loss From Continuing Operations Before Realized Gain Loss On Disposal Of Equity Method Investment IncomeLossFromContinuingOperationsBeforeRealizedGainLossOnDisposalOfEquityMethodInvestment	226510000	USD
CY2020Q2	us-gaap	Assets Assets	13071564000	USD
CY2019Q4	us-gaap	Assets Assets	12766320000	USD
CY2020Q2	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	23500000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	43100000	USD
CY2019Q2	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	25500000	USD
	us-gaap	Selling General And Administrative Expense SellingGeneralAndAdministrativeExpense	51500000	USD

Files In Submission

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$SLG
SL GREEN REALTY CORP Stock $slg

2020 Q2 Form 10-Q Financial Statement

#000104097120000022 Filed on August 10, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$SLG SL GREEN REALTY CORP Stock $slg

2020 Q2 Form 10-Q Financial Statement

#000104097120000022 Filed on August 10, 2020

Income Statement

Balance Sheet

Cashflow Statement

Facts In Submission

Files In Submission

$SLG
SL GREEN REALTY CORP Stock $slg