Net Income Per Share - Calculations of Basic and Diluted Net Income per Share and Basic and Dilutive Weighted Average Shares Outstanding (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Net Income Per Share
Net income	$ 33,171	$ 28,170	$ 106,625	$ 87,601
Weighted average shares outstanding (in shares)	83,081	87,355	83,425	89,509
Dilutive impact from:
Share-based payment awards (in shares)	292	498	417	612
Dilutive weighted average shares outstanding (in shares)	83,373	87,853	83,842	90,121
Income per share
Basic (in dollars per share)	$ 0.40	$ 0.32	$ 1.28	$ 0.98
Dilutive (in dollars per share)	$ 0.40	$ 0.32	$ 1.27	$ 0.97