Organization, Basis of Presentation, and Summary of Significant Accounting Policies - Dealer Rebates (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Dealer Rebate Accrual [Roll Forward]
Balance at beginning of year	$ 3,178	$ 3,912	$ 3,165
Add: Dealer rebate expense	15,713	12,960	6,440
Less: Dealer rebates paid	(13,332)	(13,694)	(5,693)
Balance at end of year	$ 5,559	$ 3,178	$ 3,912