Significant Accounting Policies - Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Net income	$ 33,326	$ 33,171	$ 36,683	$ 36,771	$ 30,806	$ 28,170	$ 30,464	$ 28,967	$ 139,951	$ 118,407	$ 85,783
Weighted average shares outstanding (in shares)	81,282	83,081	83,315	83,876	85,056	87,355	89,942	91,183	82,892	88,398	92,648
Dilutive impact from:
Employee equity awards (in shares)									417	618	1,017
Dilutive weighted average shares outstanding (in shares)	81,599	83,373	83,703	84,320	85,585	87,853	90,471	91,891	83,309	89,016	93,665
Income per share
Basic (in dollars per share)	$ 0.41	$ 0.40	$ 0.44	$ 0.44	$ 0.36	$ 0.32	$ 0.34	$ 0.32	$ 1.69	$ 1.34	$ 0.93
Dilutive (in dollars per share)	$ 0.41	$ 0.40	$ 0.44	$ 0.44	$ 0.36	$ 0.32	$ 0.34	$ 0.32	$ 1.68	$ 1.33	$ 0.92