Equity-Based Compensation (Tables)

12 Months Ended

Sep. 30, 2018

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Schedule of Historical Activity for Units

A summary of the Company’s historical activity for the Units is presented in the following table:

Class B Units	Shares
Outstanding at December 31, 2015		7,321
Granted		4,647
Less: Redeemed		1,524
Less: Forfeited		3,393
Outstanding at December 31, 2016		7,051
Granted		1,304
Less: Redeemed		155
Less: Forfeited		650
Outstanding at September 30, 2017		7,550

Summary of Stock Options Activity

A summary of the Company’s stock option activity for the year ended September 30, 2018 is presented in the following table:

Stock Options	Shares		Weighted Average Exercise Price
Outstanding at October 1, 2017		—
Grants in connection with the IPO		5,747	$	22.00
Less: Exercised		—
Less: Forfeited and expired units		—
Outstanding at September 30, 2018		5,747	$	22.00
Vested and exercisable at September 30, 2018		2,175
Expected to vest after September 30, 2018		3,572	$	22.00

Schedule of Weighted-Average Assumptions Used in Valuation of Unit Awards Granted or Modified

The weighted-average assumptions used in the valuation of Unit awards and stock option awards granted or modified for the year ended September 30, 2018, the nine months ended September 30, 2017 and the year ended December 31, 2016 are presented in the table below:

	Fiscal Year Ended			Nine Months Ended			Year Ended
	September 30, 2018			September 30, 2017			December 31, 2016
Assumptions:
Risk-free interest rate		2.77	%		1.37	%		1.42	%
Dividend yield		—			—			—
Volatility factor		26.93	%		46.00	%		43.00	%
Expected term (in years)		6.0			2.6			3.1