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		6 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Net Income Per Share
Net income	$ 36,683	$ 30,464	$ 73,454	$ 59,432
Weighted average shares outstanding (in shares)	83,315	89,942	83,596	90,562
Dilutive impact from:
Share-based payment awards (in shares)	388	529	439	634
Dilutive weighted average shares outstanding (in shares)	83,703	90,471	84,035	91,196
Income per share
Basic (in dollars per share)	$ 0.44	$ 0.34	$ 0.88	$ 0.66
Dilutive (in dollars per share)	$ 0.44	$ 0.34	$ 0.87	$ 0.65