v2.4.0.8

Stock Option and Incentive Plan Stock Option and Incentive Plan (Narrative) (Details) (MYLTIP 2014 [Member], USD $) | 0 Months Ended
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Jan. 27, 2014 indices tiers Y
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
TRS Measurement, Years | 3
Indices Used to Compare TRS | 2
Number of Tiers | 4
Percentage of annualized TRS for Reduction of Earned Awards | 0.00%
Percentage to Cause Some Awards to be Earned Even if on a Relative Basis it Would Not Result in any Earned Awards | 12.00%
Distributions Percent Before Measurement Date | 10.00%
Value of MYLTIP Awards | $ 12,700,000
MYLTIP Value Amortized Into Earnings, Years | 4
Cohen & Steers Realty Majors Portfolio Index [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Weighted Percentage of Index Used to Compare to TRS | 50.00%
NAREIT Office Index adjusted [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Weighted Percentage of Index Used to Compare to TRS | 50.00%
Exceptional [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Amount of Each Tier | 40,200,000
Target [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Amount of Each Tier | 13,400,000
Threshold [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Amount of Each Tier | 6,700,000
High [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Amount of Each Tier | 26,800,000
Maximum [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Potential Awards Earned | 40,200,000
Minimum [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Potential Awards Earned | $ 0
MYLTIP Vesting 2017 [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Vesting Percentage | 50.00%
Vesting Date | Feb. 03, 2017
MYLTIP vesting 2018 [Member] |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
Vesting Percentage | 50.00%
Vesting Date | Feb. 03, 2018

X
- Definition Amount of Each Tier + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Distributions Percent Before Measurement Date + References No definition available. + Details
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Namespace Prefix: | bxp_
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Balance Type: | na
Period Type: | duration

X
- Definition Indices Used to Compare TRS + References No definition available. + Details
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Balance Type: | na
Period Type: | duration

X
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Namespace Prefix: | bxp_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of Tiers + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:integerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of annualized TRS for Reduction of Earned Awards + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage to Cause Some Awards to be Earned Even if on a Relative Basis it Would Not Result in any Earned Awards + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Potential Awards Earned + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition TRS Measurement, Years. + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:positiveIntegerItemType
Balance Type: | na
Period Type: | duration

X
- Definition Value of MYLTIP Awards + References No definition available. + Details
Name: | bxp_ValueOfMyltipAwards
Namespace Prefix: | bxp_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Vesting Date. + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | xbrli:dateItemType
Balance Type: | na
Period Type: | duration

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- Definition Vesting percentage + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Weighted Percentage of Index Used to Compare to TRS + References No definition available. + Details
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Namespace Prefix: | bxp_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
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Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration