Unaudited Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Tax receivable agreement, related party	$ 111.5	$ 40.7
Class A Common Stock
Shareholders'/members' equity (deficit):
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock shares authorized (in shares)	200,000,000	200,000,000
Common stock shares issued (in shares)	36,711,625	26,025,189
Common stock shares outstanding (in shares)	36,711,625	26,025,189
Class B Common Stock
Shareholders'/members' equity (deficit):
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock shares authorized (in shares)	40,000,000	40,000,000
Common stock shares issued (in shares)	34,663,538	35,913,538
Common stock shares outstanding (in shares)	34,663,538	35,913,538
Class C Common Stock
Shareholders'/members' equity (deficit):
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock shares authorized (in shares)	4,000,000	4,000,000
Common stock shares issued (in shares)	2,333,955	2,461,055
Common stock shares outstanding (in shares)	2,333,955	2,461,055
Class D Common Stock
Shareholders'/members' equity (deficit):
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock shares authorized (in shares)	32,000,000	32,000,000
Common stock shares issued (in shares)	8,354,978	16,785,552
Common stock shares outstanding (in shares)	8,354,978	16,785,552