Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Partners capital	$ 7,047,349		$ 7,047,349		$ 6,634,493
Total revenues	2,632,570	$ 1,535,726	4,401,701	$ 3,450,444
Net income attributable to The Blackstone Group L.P.	$ 742,042	$ 337,407	$ 1,109,914	$ 789,316
Common Units, Basic	$ 1.09	$ 0.51	$ 1.64	$ 1.19
Common Units, Diluted	$ 1.09	$ 0.50	$ 1.63	$ 1.18
Net Cash provided (used) by/in Operating Activities			$ (2,660,677)	$ (422,120)
Net Cash provided (used) by/in Investing Activities			(8,898)	(13,663)
Effect of Exchange Rate Changes on Cash and Cash Equivalents, Cash Held by Blackstone Funds, and Restricted Cash			11,671	72,188
Cash and Cash Equivalents, Cash Held by Blackstone Funds and Other, and Restricted Cash	$ 1,998,926	$ 3,273,055	$ 1,998,926	3,273,055	3,936,489	$ 2,860,955
Accounting Standards Update 2014-09 [Member]
Summary Of Significant Accounting Policies [Line Items]
Partners capital					$ 1,900	2,400
Total revenues		(13,600)		(39,600)
Net income attributable to The Blackstone Group L.P.		$ (5,400)		$ (15,300)
Common Units, Basic		$ 0.01		$ 0.02
Common Units, Diluted		$ 0.01		$ 0.02
Accounting Standards Update 2014-09 [Member] | General and Administrative Expense [Member] | Management Service
Summary Of Significant Accounting Policies [Line Items]
Cost of investment management services		$ 4,300		$ 7,600
Accounting Standards Update 2016-18 [Member]
Summary Of Significant Accounting Policies [Line Items]
Net Cash provided (used) by/in Operating Activities				(463,500)
Net Cash provided (used) by/in Investing Activities				(18,000)
Effect of Exchange Rate Changes on Cash and Cash Equivalents, Cash Held by Blackstone Funds, and Restricted Cash				58,300
Cash and Cash Equivalents, Cash Held by Blackstone Funds and Other, and Restricted Cash		$ 1,500,000		$ 1,500,000		$ 1,000,000