XML 50 R35.htm IDEA: XBRL DOCUMENT v3.19.2

Basis Of Presentation And Summary Of Significant Accounting Policies Narrative (Details)	Jun. 30, 2019
Schedule of Equity Method Investments [Line Items]
Number of VIEs that are consolidated	6
In-service Properties [Member]
Schedule of Equity Method Investments [Line Items]
Number of VIEs that are consolidated	5

X

- Definition

Number of VIEs - consolidated

+ References

No definition available.

+ Details

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

X

- Definition

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

+ References

No definition available.

+ Details

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

X

- Details

Name:	us-gaap_RealEstatePropertiesAxis=bxp_TotalOfficePropertiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: