Net Contractual Sales Price

No definition available.

Name:	bxp_NetContractualSalesPrice
Namespace Prefix:	bxp_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Number of apartment units

+ References

No definition available.

+ Details

Name:	bxp_Numberofapartmentunits
Namespace Prefix:	bxp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Square Footage Of Signed Lease.

+ References

No definition available.

+ Details

Name:	bxp_SquareFootageOfSignedLease
Namespace Prefix:	bxp_
Data Type:	xbrli:positiveIntegerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of operating income (loss) attributable to disposal group, including, but not limited to, discontinued operation.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 205
-SubTopic 20
-Section 50
-Paragraph 5B
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64827811&loc=SL51721673-107760

+ Details

Name:	us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This element represents the amount of gain (loss) on sale of properties during the reporting period gross of the applicable income taxes realized.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 974
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-15.(a)(1)(ii)
-URI http://asc.fasb.org/extlink&oid=6875705&loc=d3e641549-123027

+ Details

Name:	us-gaap_GainLossOnSaleOfPropertiesBeforeApplicableIncomeTaxes
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Net rentable area for properties owned.

+ References

No definition available.

+ Details

Name:	us-gaap_NetRentableArea
Namespace Prefix:	us-gaap_
Data Type:	num:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Cash received from the sale of real estate that is held for investment, that is, it is part of an investing activity during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3179-108585

+ Details

Name:	us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

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

+ References

No definition available.

+ Details

Name:	us-gaap_RealEstateLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=bxp_SeventeenFiftyPresidentsStreetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=bxp_RestonsignaturesiteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RealEstateAndAccumulatedDepreciationDescriptionOfPropertyAxis=bxp_RestonGatewayMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_ConsolidatedEntitiesAxis=us-gaap_SubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis=bxp_FiveZeroZeroEStreetMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Real Estate Narrative (Details) $ in Thousands				3 Months Ended
Real Estate Narrative (Details) $ in Thousands	Feb. 23, 2018 ft²	Jan. 09, 2018 USD ($) ft²	Jan. 08, 2018 USD ($)	Mar. 31, 2018 USD ($)	Mar. 31, 2017 USD ($)	Jan. 31, 2018 ft² apartments	Jan. 24, 2018 ft²
Real Estate [Line Items]
Proceeds from sales of real estate				$ 116,120	$ 133
Gains on sales of real estate				96,397	133
17Fifty Presidents Street [Member]
Real Estate [Line Items]
Net Rentable Area (in sf) \| ft²							276,000
Signature at Reston [Member]
Real Estate [Line Items]
Net Rentable Area (in sf) \| ft²						515,000
Number of apartment units \| apartments						508
Reston Gateway [Member]
Real Estate [Line Items]
Net Rentable Area (in sf) \| ft²	1,100,000.0
Square Footage Of Signed Lease \| ft²	850,000
Boston Properties Limited Partnership
Real Estate [Line Items]
Proceeds from sales of real estate				116,120	133
Gains on sales of real estate				$ 98,907	133
500 E Street [Member]
Real Estate [Line Items]
Net Rentable Area (in sf) \| ft²		262,000
Net Contractual Sales Price		$ 118,600
Net income (loss)			$ 100		$ 1,600
Proceeds from sales of real estate		116,100
Gains on sales of real estate		96,400
500 E Street [Member] \| Boston Properties Limited Partnership
Real Estate [Line Items]
Gains on sales of real estate		$ 98,900