Financial Assets and Liabilities at Fair Value (Detail) - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Accounts Receivable - Loans and Receivables		$ 163,135	$ 239,659
Assets		7,186,737	12,649,547
Securities Sold, Not Yet Purchased		167,457	154,380
Liabilities		5,830,973	11,339,206
Freestanding Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives assets		5,591	8,801
Derivatives liabilities		69,793	36,234
Net Investment Hedges
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives liabilities			453
Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments			458
Corporate Loans | Assets Of Consolidated CLO Vehicles
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		6,057,153	10,825,759
Corporate Bonds | Assets Of Consolidated CLO Vehicles
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments			690,125
Liabilities of Consolidated CLO Vehicles | Senior Secured Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Loan payable		5,612,150	10,594,656
Fair value of due to Affiliates		3,269	996
Liabilities of Consolidated CLO Vehicles | Subordinated Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Loan payable		150,220	703,164
Fair value of due to Affiliates		65,334	40,390
Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents - Money Market Funds		492,345	853,680
Total Investments		10,337,431	15,842,638
Accounts Receivable - Loans and Receivables		163,135	239,659
Derivatives assets			4,443
Assets		10,995,682	16,940,420
Total Other Assets		2,771
Fair value of due to Affiliates		68,603	41,386	[1]
Securities Sold, Not Yet Purchased		167,457	154,380
Total Accounts Payable, Accrued Expenses and Other Liabilities		69,793	41,798
Liabilities		6,068,223	11,535,384
Fair Value, Measurements, Recurring | Freestanding Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives liabilities		64,460	30,554
Fair Value, Measurements, Recurring | Freestanding Derivatives | Foreign Currency Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives assets		2,151	2,097
Derivatives liabilities		1,093	2,975
Fair Value, Measurements, Recurring | Freestanding Derivatives | Interest Rate Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives assets		570	2,042
Derivatives liabilities		63,103	27,275
Fair Value, Measurements, Recurring | Net Investment Hedges | Foreign Currency Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives liabilities			453
Fair Value, Measurements, Recurring | Other Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		326,737	322,474
Fair Value, Measurements, Recurring | Credit Default Swap | Freestanding Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives assets		50	304
Derivatives liabilities		264	304
Fair Value, Measurements, Recurring | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		462,436	465,460
Assets		462,436	465,460
Fair Value, Measurements, Recurring | Net Asset Value | Other Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		19,732	19,847
Fair Value, Measurements, Recurring | Liabilities of Consolidated CLO Vehicles
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Loan payable		5,762,370	11,297,820	[1]
Fair value of due to Affiliates	[1],[2]		40,390
Fair Value, Measurements, Recurring | Liabilities of Consolidated CLO Vehicles | Senior Secured Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Loan payable	[2]	5,612,150	10,594,656	[1]
Fair value of due to Affiliates	[2]	3,269	996	[1]
Fair Value, Measurements, Recurring | Liabilities of Consolidated CLO Vehicles | Subordinated Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Loan payable	[2]	150,220	703,164	[1]
Fair value of due to Affiliates	[2]	65,334
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	7,560,831	12,954,121
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Freestanding Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives liabilities		5,333	10,791
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Freestanding Derivatives | Total Return Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	772	526
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Freestanding Derivatives | Foreign Currency Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	2,922	101
Derivatives liabilities		1,014	5,628	[1]
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Assets Of Consolidated CLO Vehicles | Freestanding Derivatives | Foreign Currency Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]		23,986
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]		458
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Investment Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	124,736	130,339
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	249,878	243,336
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Partnership And LLC Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	329,905	333,997
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Debt Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	793,646	701,763
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Corporate Loans | Assets Of Consolidated CLO Vehicles
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	6,057,153	10,825,759
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Corporate Bonds | Assets Of Consolidated CLO Vehicles
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]		690,125
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Credit Default Swap | Freestanding Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	1,819	3,731
Derivatives liabilities		4,319	5,163	[1]
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	124,736	130,339
Fair Value, Measurements, Recurring | Consolidated Blackstone Funds | Net Asset Value | Investment Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	124,736	130,339
Fair Value, Measurements, Recurring | Corporate Treasury Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		2,449,863	2,566,043
Fair Value, Measurements, Recurring | Corporate Treasury Investments | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		317,968	315,274
Fair Value, Measurements, Recurring | Corporate Treasury Investments | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		281,273	282,866
Fair Value, Measurements, Recurring | Corporate Treasury Investments | Debt Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		1,850,622	1,967,903
Fair Value, Measurements, Recurring | Corporate Treasury Investments | Net Asset Value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		317,968	315,274
Fair Value, Measurements, Recurring | Corporate Treasury Investments | Net Asset Value | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		317,968	315,274
Fair Value, Measurements, Recurring | Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash and Cash Equivalents - Money Market Funds		492,345	853,680
Total Investments		534,339	543,381
Derivatives assets			575
Assets		1,026,987	1,397,636
Total Other Assets		303
Total Accounts Payable, Accrued Expenses and Other Liabilities		1,369	415
Liabilities		1,369	415
Fair Value, Measurements, Recurring | Level 1 | Freestanding Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives liabilities		1,369	415
Fair Value, Measurements, Recurring | Level 1 | Freestanding Derivatives | Interest Rate Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives assets		303	575
Derivatives liabilities		1,369	415
Fair Value, Measurements, Recurring | Level 1 | Other Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		195,685	193,072
Fair Value, Measurements, Recurring | Level 1 | Consolidated Blackstone Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	57,381	67,443
Fair Value, Measurements, Recurring | Level 1 | Consolidated Blackstone Funds | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	57,381	67,443
Fair Value, Measurements, Recurring | Level 1 | Corporate Treasury Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		281,273	282,866
Fair Value, Measurements, Recurring | Level 1 | Corporate Treasury Investments | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		281,273	282,866
Fair Value, Measurements, Recurring | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		8,260,156	13,684,784
Derivatives assets			3,868
Assets		8,262,624	13,688,652
Total Other Assets		2,468
Fair value of due to Affiliates		68,603	41,386	[1]
Securities Sold, Not Yet Purchased		167,457	154,380
Total Accounts Payable, Accrued Expenses and Other Liabilities		68,424	41,383
Liabilities		6,066,854	11,534,969
Fair Value, Measurements, Recurring | Level 2 | Freestanding Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives liabilities		63,091	30,139
Fair Value, Measurements, Recurring | Level 2 | Freestanding Derivatives | Foreign Currency Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives assets		2,151	2,097
Derivatives liabilities		1,093	2,975
Fair Value, Measurements, Recurring | Level 2 | Freestanding Derivatives | Interest Rate Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives assets		267	1,467
Derivatives liabilities		61,734	26,860
Fair Value, Measurements, Recurring | Level 2 | Net Investment Hedges | Foreign Currency Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives liabilities			453
Fair Value, Measurements, Recurring | Level 2 | Other Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		13,917	14,162
Fair Value, Measurements, Recurring | Level 2 | Credit Default Swap | Freestanding Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives assets		50	304
Derivatives liabilities		264	304
Fair Value, Measurements, Recurring | Level 2 | Liabilities of Consolidated CLO Vehicles
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Loan payable		5,762,370	11,297,820	[1]
Fair value of due to Affiliates	[1],[2]		40,390
Fair Value, Measurements, Recurring | Level 2 | Liabilities of Consolidated CLO Vehicles | Senior Secured Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Loan payable	[2]	5,612,150	10,594,656	[1]
Fair value of due to Affiliates	[2]	3,269	996	[1]
Fair Value, Measurements, Recurring | Level 2 | Liabilities of Consolidated CLO Vehicles | Subordinated Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of Loan payable	[2]	150,220	703,164	[1]
Fair value of due to Affiliates	[2]	65,334
Fair Value, Measurements, Recurring | Level 2 | Consolidated Blackstone Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	6,415,563	11,726,968
Fair Value, Measurements, Recurring | Level 2 | Consolidated Blackstone Funds | Freestanding Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivatives liabilities		5,333	10,791
Fair Value, Measurements, Recurring | Level 2 | Consolidated Blackstone Funds | Freestanding Derivatives | Total Return Swaps
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	772	526
Fair Value, Measurements, Recurring | Level 2 | Consolidated Blackstone Funds | Freestanding Derivatives | Foreign Currency Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	2,922	101
Derivatives liabilities		1,014	5,628	[1]
Fair Value, Measurements, Recurring | Level 2 | Consolidated Blackstone Funds | Assets Of Consolidated CLO Vehicles | Freestanding Derivatives | Foreign Currency Contracts
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]		23,986
Fair Value, Measurements, Recurring | Level 2 | Consolidated Blackstone Funds | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	52,225	44,026
Fair Value, Measurements, Recurring | Level 2 | Consolidated Blackstone Funds | Partnership And LLC Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	1,956	2,549
Fair Value, Measurements, Recurring | Level 2 | Consolidated Blackstone Funds | Debt Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	709,597	643,608
Fair Value, Measurements, Recurring | Level 2 | Consolidated Blackstone Funds | Corporate Loans | Assets Of Consolidated CLO Vehicles
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	5,646,272	10,318,316
Fair Value, Measurements, Recurring | Level 2 | Consolidated Blackstone Funds | Corporate Bonds | Assets Of Consolidated CLO Vehicles
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]		690,125
Fair Value, Measurements, Recurring | Level 2 | Consolidated Blackstone Funds | Credit Default Swap | Freestanding Derivatives
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	1,819	3,731
Derivatives liabilities		4,319	5,163	[1]
Fair Value, Measurements, Recurring | Level 2 | Corporate Treasury Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		1,830,676	1,943,654
Fair Value, Measurements, Recurring | Level 2 | Corporate Treasury Investments | Debt Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		1,830,676	1,943,654
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		1,080,500	1,149,013
Accounts Receivable - Loans and Receivables		163,135	239,659
Assets		1,243,635	1,388,672
Fair Value, Measurements, Recurring | Level 3 | Other Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		97,403	95,393
Fair Value, Measurements, Recurring | Level 3 | Consolidated Blackstone Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	963,151	1,029,371
Assets		963,151	1,029,371
Fair Value, Measurements, Recurring | Level 3 | Consolidated Blackstone Funds | Other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]		458
Fair Value, Measurements, Recurring | Level 3 | Consolidated Blackstone Funds | Equity Securities
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	140,272	131,867
Fair Value, Measurements, Recurring | Level 3 | Consolidated Blackstone Funds | Partnership And LLC Interests
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	327,949	331,448
Fair Value, Measurements, Recurring | Level 3 | Consolidated Blackstone Funds | Debt Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	84,049	58,155
Fair Value, Measurements, Recurring | Level 3 | Consolidated Blackstone Funds | Corporate Loans | Assets Of Consolidated CLO Vehicles
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments	[1]	410,881	507,443
Fair Value, Measurements, Recurring | Level 3 | Corporate Treasury Investments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		19,946	24,249
Fair Value, Measurements, Recurring | Level 3 | Corporate Treasury Investments | Debt Instruments
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total Investments		$ 19,946	$ 24,249

[1] Pursuant to GAAP consolidation guidance, the Partnership is required to consolidate all VIEs in which it has been identified as the primary beneficiary, including certain CLO vehicles and other funds in which a consolidated entity of the Partnership, as the general partner of the fund, has a controlling financial interest. While the Partnership is required to consolidate certain funds, including CLO vehicles, for GAAP purposes, the Partnership has no ability to utilize the assets of these funds and there is no recourse to the Partnership for their liabilities since these are client assets and liabilities.

[2] Senior and subordinate notes issued by CLO vehicles are classified based on the more observable fair value of CLO assets less (a) the fair value of any beneficial interests held by Blackstone, and (b) the carrying value of any beneficial interests that represent compensation for services.