Condensed Consolidated Statements Of Shareholders' Equity - USD ($) $ in Thousands	Total	Common Stock Outstanding [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]	Treasury Stock [Member]
Balance (in shares) at Jun. 30, 2022		27,520,000
Balance at Jun. 30, 2022	$ 844,687	$ 137,814	$ 1,485,045	$ (11,172)	$ (767,000)
Net income	37,592		37,592
Net pension and postretirement benefit gains, net of tax effect	95			95
Cash dividends - common stock	(22,067)		(22,067)
Purchase of treasury stock (in shares)		0
Purchase of treasury stock	(84)				(84)
Stock-based plans (in shares)		34,000
Stock-based plans	(617)	$ (617)
Stock-based compensation expense	2,465	$ 2,465
Balance (in shares) at Sep. 30, 2022		27,554,000
Balance at Sep. 30, 2022	$ 862,071	$ 139,662	1,500,570	(11,077)	(767,084)
Balance (in shares) at Jun. 30, 2023	27,527,550	27,528,000
Balance at Jun. 30, 2023	$ 862,267	$ 143,870	1,503,963	(9,365)	(776,201)
Net income	43,951		43,951
Net pension and postretirement benefit gains, net of tax effect	76			76
Cash dividends - common stock	(23,445)		(23,445)
Purchase of treasury stock (in shares)		(40,000)
Purchase of treasury stock	(6,650)				(6,650)
Stock-based plans (in shares)		29,000
Stock-based plans	0	$ 0
Stock-based compensation expense	$ 2,569	$ 2,569
Balance (in shares) at Sep. 30, 2023	27,517,313	27,517,000
Balance at Sep. 30, 2023	$ 878,768	$ 146,439	$ 1,524,469	$ (9,289)	$ (782,851)