Equity-Based Compensation - Unvested Units After Expected Forfeitures which are Expected to Vest (Details)	9 Months Ended
	Sep. 30, 2016 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Units expected to vest	16,520,038
Weighted-average service period of unit expected to vest (in years)	2 years 2 months 12 days
Restricted Stock Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Units expected to vest	5,673,576
Weighted-average service period of unit expected to vest (in years)	1 year 6 months
PJT Partners Holdings LP | Partnership Units
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Units expected to vest	10,846,462
Weighted-average service period of unit expected to vest (in years)	2 years 6 months