Tax Receivable Agreement (Details) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended
	Feb. 12, 2018	Sep. 30, 2019	Sep. 30, 2019
Tax receivable agreement
Tax savings payable to TRA Holders (as a percent)	85.00%
Tax savings benefit recorded as APIC (as a percent)	15.00%
Total TRA liability		$ 220,920	$ 220,920
Amount of expected change in benefits subject to the TRA from stock price increases or decreases, as a percentage of the tax-effected change in price			125.00%
Amount of expected change in undiscounted amounts payable under the TRA from stock price changes, as a percentage of the tax-effected change in price			106.00%
Payment period, after redemption	20 years
Variable reference rate	one-year LIBOR
TRA payment period			5 days
TRA payment		9,300
TRA tax benefit		10,800
TRA interest accrued		$ 200
Minimum
Tax receivable agreement
Aggregate payment period	25 years
One-year LIBOR
Tax receivable agreement
Applicable margin rate (as a percent)	1.50%
Variable interest rate, deferral period			5.50%