Reconciliation of Realized and Net Change in Unrealized Gains (Losses) to Other Income (Loss) - Net Gains (Losses) from Fund Investment Activities in Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Gain (Loss) on Securities [Line Items]
Realized and Net Change in Unrealized Gains from Consolidated Blackstone Funds	$ 1,148,679	$ 1,051,648
Interest and Dividend Revenue Attributable to Consolidated Blackstone Funds	44,084	35,385
Other Income - Net Gains from Fund Investment Activities	130,325	110,599
Consolidated Blackstone Funds
Gain (Loss) on Securities [Line Items]
Realized Losses	(2,912)	(17,858)
Net Change in Unrealized Gains	106,003	97,241
Realized and Net Change in Unrealized Gains from Consolidated Blackstone Funds	103,091	79,383
Interest and Dividend Revenue Attributable to Consolidated Blackstone Funds	27,234	31,216
Other Income - Net Gains from Fund Investment Activities	$ 130,325	$ 110,599