Summary Of Significant Accounting Policies (Schedule Of Basic And Diluted Net Income Per Common Share Calculations) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Net income	$ 47,907	$ 45,920	$ 86,935	$ 75,306
Net income available to participating securities	(96)	(73)	(176)	(119)
Net income available to common shareholders	$ 47,811	$ 45,847	$ 86,759	$ 75,187
Weighted average common shares outstanding - basic (in shares)	27,435	27,396	27,429	27,396
Incremental share effect from:
Nonparticipating restricted stock (in shares)	2	3	4	4
Stock-settled stock appreciation rights (in shares)	129	61	107	56
Weighted average common shares outstanding - diluted (in shares)	27,566	27,460	27,540	27,456
Net income per common share - basic (in dollars per share)	$ 1.74	$ 1.67	$ 3.16	$ 2.74
Net income per common share - diluted (in dollars per share)	$ 1.73	$ 1.67	$ 3.15	$ 2.74