Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share, Basic and Diluted [Abstract]
NET INCOME	$ 60,993	$ 59,252	$ 68,089	$ 83,551	$ 67,836	$ 69,085	$ 161,243	$ 66,870	$ 271,885	$ 365,034	$ 229,561
Common share information:
Basic weighted average shares outstanding	77,060	77,177	77,216	77,188	77,261	77,247	77,218	77,283	77,160	77,252	77,856
Dilutive effect of stock options and restricted stock									187	333	399
Diluted weighted average shares outstanding	77,157	77,286	77,409	77,537	77,585	77,546	77,565	77,646	77,347	77,585	78,255
Basic earnings per share	$ 0.79	$ 0.77	$ 0.88	$ 1.08	$ 0.88	$ 0.89	$ 2.09	$ 0.87	$ 3.52	$ 4.73	$ 2.95
Diluted earnings per share	$ 0.79	$ 0.77	$ 0.88	$ 1.08	$ 0.87	$ 0.89	$ 2.08	$ 0.86	$ 3.52	$ 4.70	$ 2.93
Antidilutive stock options and restricted stock excluded from computation of earnings per share									0	41	32