v2.4.1.9

Carrying Value and Fair Value of Blackstone Issued Notes (Detail) (USD $)
In Thousands, unless otherwise specified

Mar. 31, 2015

Dec. 31, 2014

6.625% Notes

Debt Instrument [Line Items]

Carrying value of issued notes

$ 623,121us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= bx_SixPointSixTwoFivePercentNotesMember

^[1]

$ 625,111us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= bx_SixPointSixTwoFivePercentNotesMember

^[1]

Debt instrument, fair value

694,044us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= bx_SixPointSixTwoFivePercentNotesMember

^[1],[2]

684,158us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= bx_SixPointSixTwoFivePercentNotesMember

^[1],[2]

5.875% Notes

Debt Instrument [Line Items]

Carrying value of issued notes

398,753us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= bx_FivePointEightSevenFivePercentNotesMember

398,710us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= bx_FivePointEightSevenFivePercentNotesMember

Debt instrument, fair value

472,400us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= bx_FivePointEightSevenFivePercentNotesMember

^[2]

462,360us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= bx_FivePointEightSevenFivePercentNotesMember

^[2]

4.750% Notes

Debt Instrument [Line Items]

Carrying value of issued notes

393,960us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= bx_FourPointSevenFiveZeroPercentNotesMember

393,805us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= bx_FourPointSevenFiveZeroPercentNotesMember

Debt instrument, fair value

445,680us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= bx_FourPointSevenFiveZeroPercentNotesMember

^[2]

436,240us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= bx_FourPointSevenFiveZeroPercentNotesMember

^[2]

6.250% Notes

Debt Instrument [Line Items]

Carrying value of issued notes

239,897us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= bx_SixPointTwoFiveZeroPercentNotesMember

239,864us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= bx_SixPointTwoFiveZeroPercentNotesMember

Debt instrument, fair value

320,900us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= bx_SixPointTwoFiveZeroPercentNotesMember

^[2]

307,125us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= bx_SixPointTwoFiveZeroPercentNotesMember

^[2]

5.000% Notes

Debt Instrument [Line Items]

Carrying value of issued notes

493,039us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= bx_FivePointZeroZeroZeroPercentNotesMember

493,013us-gaap_DebtInstrumentCarryingAmount
/ us-gaap_DebtInstrumentAxis
= bx_FivePointZeroZeroZeroPercentNotesMember

Debt instrument, fair value

$ 544,900us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= bx_FivePointZeroZeroZeroPercentNotesMember

^[2]

$ 527,500us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= bx_FivePointZeroZeroZeroPercentNotesMember

^[2]

[1]	The carrying and fair values are determined using the original $600 million par amount less $15 million attributable to these notes which were acquired but not retired by Blackstone during 2012.
[2]	Fair value is determined by broker quote and these notes would be classified as Level II within the fair value hierarchy.

X

- Definition

Amount of long-term debt before deduction of unamortized discount or premium. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt, with initial maturities beyond one year or the normal operating cycle, if longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 20

-Article 5



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.22)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682



Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 22

-Article 5



Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 16

-Article 9

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13433-108611



Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 12

-URI http://asc.fasb.org/extlink&oid=35750535&loc=d3e13476-108611

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Details

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

X

- Details

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Namespace Prefix:
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X

- Details

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X

- Details

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X

- Details

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X

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