v2.4.0.8

Noncontrolling Interests (Narrative) (Details) | Jun. 30, 2013
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Noncontrolling Interests [Member] |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |
Operating Partnership (OP) Units (in shares) | 15,739,523
Long-Term Incentive Plan (LTIP) Units (in shares) | 1,464,250
Series Two Preferred Units (in shares) | 995,997
Convertible Operating Partnership (OP) Units (in shares) | 1,307,083
Series Four Preferred Units (in shares) | 1,221,527
OPP Units 2011 [Member] |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |
Outperformance awards in LTIP Units (in shares) | 397,750
OPP Units 2012 [Member] |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |
Outperformance awards in LTIP Units (in shares) | 397,750
MYLTIP [Member] |
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items] |
2013 MYLTIP | 317,406

X
- Definition 2013 MYLTIP + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Long Term Incentive Plan Units + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition OP Units + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Outperformance Awards Long Term Incentive Plan Units + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Series Four Preferred Units + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Series Two Preferred Units + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Definition Series Two Preferred Units On Converted Basis + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
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Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration