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, 2021	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Net income	$ 34,370	$ 30,655	$ 44,630	$ 37,079	$ 65,025	$ 81,709
Net income available to participating securities	(98)		(94)		(185)	(173)
Net income available to common shareholders	$ 34,272		$ 44,536		$ 64,840	$ 81,536
Weighted average common shares outstanding - basic (in shares)	27,443		27,479		27,451	27,470
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental share effect from stock-settled stock appreciation rights (in shares)	19		37		34	34
Weighted average common shares outstanding - diluted (in shares)	27,464		27,518		27,490	27,507
Net income per common share - basic (in dollars per share)	$ 1.25		$ 1.62		$ 2.36	$ 2.97
Net income per common share - diluted (in dollars per share)	$ 1.25		$ 1.62		$ 2.36	$ 2.96
Nonparticipating restricted stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental share effect from awards with forfeitable dividends (in shares)	2		2		3	3
Performance units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental share effect from awards with forfeitable dividends (in shares)	0		0		2	0