Summary of Significant Accounting Policies - Liquidity (Details) - USD ($) $ in Thousands			2 Months Ended
	May 03, 2017	May 02, 2017	Jun. 30, 2017
Debt Instrument [Line Items]
Issuance of Class A common stock sold in initial public offering, net of underwriters' discounts and commissions and offering expenses			$ 205,925
Floor Plan Facility | Line of Credit
Debt Instrument [Line Items]
Line of credit facility, remaining borrowing capacity			$ 33,200
Class A | IPO
Debt Instrument [Line Items]
Issuance of Class A common stock sold in initial public offering, net of underwriters' discounts and commissions and offering expenses	$ 205,900	$ 205,900