Net Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2015
Treasury Stock, Value, Acquired, Cost Method									$ 375,000	$ 180,066	$ 298,344
Net Income (Loss) Attributable to Parent	$ 54,352	$ 35,834	$ 37,010	$ 35,000	$ 33,326	$ 33,171	$ 36,683	$ 36,771	$ 162,196	$ 139,951	$ 118,407
Weighted Average Number of Shares Outstanding, Basic	74,294,000	75,676,000	76,905,000	79,048,000	81,282,000	83,081,000	83,315,000	83,876,000	76,491,000	82,892,000	88,398,000
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements									487,000	417,000	618,000
Weighted Average Number of Shares Outstanding, Diluted	74,830,000	76,182,000	77,318,000	79,385,000	81,599,000	83,373,000	83,703,000	84,320,000	76,978,000	83,309,000	89,016,000
Earnings Per Share, Basic	$ 0.73	$ 0.47	$ 0.48	$ 0.44	$ 0.41	$ 0.40	$ 0.44	$ 0.44	$ 2.12	$ 1.69	$ 1.34
Earnings Per Share, Diluted	$ 0.73	$ 0.47	$ 0.48	$ 0.44	$ 0.41	$ 0.40	$ 0.44	$ 0.44	$ 2.11	$ 1.68	$ 1.33
Employee Stock Option [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									27,778
Stock Compensation Plan [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									525,000	1,028,000	587,000
Employee Stock Option [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit									$ 54.22
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit									$ 63.05
Accelerated Share Repurchase Program [Member]
Treasury Stock, Value, Acquired, Cost Method									$ 100,000