Carrying Value and Fair Value of Blackstone Issued Notes (Detail) - Senior Secured Notes - USD ($) $ in Thousands		Mar. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Carrying Value		$ 3,542,077	$ 3,514,815
Debt instrument, fair value	[1]	3,762,026	3,836,528
5.875% Notes
Debt Instrument [Line Items]
Carrying Value		398,620	398,514
Debt instrument, fair value	[1]	429,480	438,320
4.750% Notes
Debt Instrument [Line Items]
Carrying Value		394,389	394,137
Debt instrument, fair value	[1]	422,080	434,200
6.250% Notes
Debt Instrument [Line Items]
Carrying Value		238,069	238,019
Debt instrument, fair value	[1]	314,100	328,200
5.000% Notes
Debt Instrument [Line Items]
Carrying Value		488,588	488,536
Debt instrument, fair value	[1]	551,700	574,100
4.450% Notes
Debt Instrument [Line Items]
Carrying Value		343,953	343,925
Debt instrument, fair value	[1]	358,610	372,575
2.000% Notes
Debt Instrument [Line Items]
Carrying Value		364,305	355,425
Debt instrument, fair value	[1]	392,099	385,433
1.000% Notes
Debt Instrument [Line Items]
Carrying Value		727,645	709,871
Debt instrument, fair value	[1]	720,657	711,440
3.150% Notes
Debt Instrument [Line Items]
Carrying Value		296,477	296,399
Debt instrument, fair value	[1]	286,590	295,320
4.000% Notes
Debt Instrument [Line Items]
Carrying Value		290,031	289,989
Debt instrument, fair value	[1]	$ 286,710	$ 296,940

[1] Fair value is determined by broker quote and these notes would be classified as Level II within the fair value hierarchy.