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, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Mar. 31, 2019	Mar. 31, 2018
Net income	$ 61,587	$ 59,217	$ 38,066	$ 37,835			$ 158,869	$ 110,668
Weighted average shares outstanding (in shares)	69,423			71,828			70,286	72,402
Dilutive impact from:
Share-based payment awards (in shares)	737						856
Dilutive weighted average shares outstanding (in shares)	70,160			72,663			71,142	73,136
Income per share
Basic (in dollars per share)	$ 0.89			$ 0.53			$ 2.26	$ 1.53
Dilutive (in dollars per share)	$ 0.88			$ 0.52			$ 2.23	$ 1.51
Accounting Standards Update 2014-09 [Member]
Net income				$ 44,505	$ 132,031	$ 40,521		$ 217,057
Weighted average shares outstanding (in shares)				71,828				72,402
Dilutive impact from:
Share-based payment awards (in shares)				835				734
Dilutive weighted average shares outstanding (in shares)				72,663				73,136
Income per share
Basic (in dollars per share)				$ 0.62				$ 3.00
Dilutive (in dollars per share)				$ 0.61				$ 2.97