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, 2023	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2023	Dec. 31, 2022
Accounting Policies [Abstract]
Net income	$ 51,484	$ 43,951	$ 39,973	$ 37,592	$ 95,435	$ 77,565
Net income available to participating securities	(157)		(118)		(292)	(232)
Net income available to common shareholders	$ 51,327		$ 39,855		$ 95,143	$ 77,333
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average common shares outstanding - basic (in shares)	27,425		27,471		27,437	27,460
Weighted average common shares outstanding - diluted (in shares)	27,440		27,493		27,457	27,476
Net income per common share – basic	$ 1.87		$ 1.45		$ 3.47	$ 2.82
Net income per common share – diluted	$ 1.87		$ 1.45		$ 3.47	$ 2.81
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)	3		2		3	3
Stock Settled Stock Appreciation Rights SARS [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental share effect from stock-settled stock appreciation rights (in shares)	7		18		9	9
Weighted average number of antidilutive securities (in rights outstanding)	100		100		100	200
Performance Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Incremental share effect from awards with forfeitable dividends (in shares)	5		2		8	4