Earnings 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, Basic and Diluted [Abstract]
Net Income	$ 84,270	$ 53,883	$ 59,348	$ 51,366	$ 60,539	$ 50,712	$ 53,882	$ 46,088	$ 248,867	$ 211,221	$ 186,715
Common share information:
Basic weighted average shares outstanding	78,841	78,805	79,473	80,545	80,904	80,880	81,432	82,195	79,416	81,353	84,866
Dilutive effect of stock options and restricted stock									318	248	530
Diluted weighted average shares outstanding	79,261	79,167	79,770	80,735	81,086	81,094	81,634	82,589	79,734	81,601	85,396
Basic earnings per share	$ 1.07	$ 0.68	$ 0.75	$ 0.64	$ 0.75	$ 0.63	$ 0.66	$ 0.56	$ 3.13	$ 2.60	$ 2.20
Diluted earnings per share	$ 1.06	$ 0.68	$ 0.74	$ 0.64	$ 0.75	$ 0.63	$ 0.66	$ 0.56	$ 3.12	$ 2.59	$ 2.19
Antidilutive stock options and restricted stock excluded from computation of earnings per share									0	0	24