Segment Information - Reconciliation of Total Segment Profit to Income before Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Reconciliation to Income Before Income Taxes
Segment profit	$ 56,299	$ 46,521	$ 111,728	$ 91,155
General and administrative	(13,805)	(10,226)	(26,667)	(22,451)
Other income (expense), net	(157)	(248)	739	(60)
Interest income (net)	58	128	139	261
Income before provision for income taxes	56,200	46,401	112,606	91,356
Operating segments
Reconciliation to Income Before Income Taxes
Segment profit	$ 70,104	$ 56,747	$ 138,395	$ 113,606