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
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6.625% Notes |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Carrying value of issued notes | $ 623,121 us-gaap_DebtInstrumentCarryingAmount / us-gaap_DebtInstrumentAxis = bx_SixPointSixTwoFivePercentNotesMember | [1] | $ 625,111 us-gaap_DebtInstrumentCarryingAmount / us-gaap_DebtInstrumentAxis = bx_SixPointSixTwoFivePercentNotesMember | [1]
Debt instrument, fair value | 694,044 us-gaap_DebtInstrumentFairValue / us-gaap_DebtInstrumentAxis = bx_SixPointSixTwoFivePercentNotesMember | [1],[2] | 684,158 us-gaap_DebtInstrumentFairValue / us-gaap_DebtInstrumentAxis = bx_SixPointSixTwoFivePercentNotesMember | [1],[2]
5.875% Notes |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Carrying value of issued notes | 398,753 us-gaap_DebtInstrumentCarryingAmount / us-gaap_DebtInstrumentAxis = bx_FivePointEightSevenFivePercentNotesMember |  | 398,710 us-gaap_DebtInstrumentCarryingAmount / us-gaap_DebtInstrumentAxis = bx_FivePointEightSevenFivePercentNotesMember |
Debt instrument, fair value | 472,400 us-gaap_DebtInstrumentFairValue / us-gaap_DebtInstrumentAxis = bx_FivePointEightSevenFivePercentNotesMember | [2] | 462,360 us-gaap_DebtInstrumentFairValue / us-gaap_DebtInstrumentAxis = bx_FivePointEightSevenFivePercentNotesMember | [2]
4.750% Notes |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Carrying value of issued notes | 393,960 us-gaap_DebtInstrumentCarryingAmount / us-gaap_DebtInstrumentAxis = bx_FourPointSevenFiveZeroPercentNotesMember |  | 393,805 us-gaap_DebtInstrumentCarryingAmount / us-gaap_DebtInstrumentAxis = bx_FourPointSevenFiveZeroPercentNotesMember |
Debt instrument, fair value | 445,680 us-gaap_DebtInstrumentFairValue / us-gaap_DebtInstrumentAxis = bx_FourPointSevenFiveZeroPercentNotesMember | [2] | 436,240 us-gaap_DebtInstrumentFairValue / us-gaap_DebtInstrumentAxis = bx_FourPointSevenFiveZeroPercentNotesMember | [2]
6.250% Notes |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Carrying value of issued notes | 239,897 us-gaap_DebtInstrumentCarryingAmount / us-gaap_DebtInstrumentAxis = bx_SixPointTwoFiveZeroPercentNotesMember |  | 239,864 us-gaap_DebtInstrumentCarryingAmount / us-gaap_DebtInstrumentAxis = bx_SixPointTwoFiveZeroPercentNotesMember |
Debt instrument, fair value | 320,900 us-gaap_DebtInstrumentFairValue / us-gaap_DebtInstrumentAxis = bx_SixPointTwoFiveZeroPercentNotesMember | [2] | 307,125 us-gaap_DebtInstrumentFairValue / us-gaap_DebtInstrumentAxis = bx_SixPointTwoFiveZeroPercentNotesMember | [2]
5.000% Notes |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Carrying value of issued notes | 493,039 us-gaap_DebtInstrumentCarryingAmount / us-gaap_DebtInstrumentAxis = bx_FivePointZeroZeroZeroPercentNotesMember |  | 493,013 us-gaap_DebtInstrumentCarryingAmount / us-gaap_DebtInstrumentAxis = bx_FivePointZeroZeroZeroPercentNotesMember |
Debt instrument, fair value | $ 544,900 us-gaap_DebtInstrumentFairValue / us-gaap_DebtInstrumentAxis = bx_FivePointZeroZeroZeroPercentNotesMember | [2] | $ 527,500 us-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.

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