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, 2018		27,488,000
Balance at Jun. 30, 2018	$ 652,282	$ 119,232	$ 1,279,343	$ (8,259)	$ (738,034)
Net income	39,028		39,028
Net pension and postretirement benefit gains, net of tax effect	44			44
Cash dividends - common stock	(16,495)		(16,495)
Purchase of treasury stock (in shares)		(10,000)
Purchase of treasury stock	(1,593)				(1,593)
Stock-based plans (in shares)		12,000
Stock-based plans	(778)	$ (778)
Stock-based compensation expense	1,531	$ 1,531
Balance (in shares) at Sep. 30, 2018		27,490,000
Balance at Sep. 30, 2018	$ 674,019	$ 119,985	1,301,876	(8,215)	(739,627)
Balance (in shares) at Jun. 30, 2019	27,491,497	27,491,000
Balance at Jun. 30, 2019	$ 726,873	$ 122,844	1,359,782	(10,308)	(745,445)
Net income	40,745		40,745
Net pension and postretirement benefit gains, net of tax effect	70			70
Cash dividends - common stock	(17,869)		(17,869)
Purchase of treasury stock (in shares)		(10,000)
Purchase of treasury stock	(1,465)				(1,465)
Stock-based plans (in shares)		4,000
Stock-based plans	(125)	$ (125)
Stock-based compensation expense	$ 1,436	$ 1,436
Balance (in shares) at Sep. 30, 2019	27,484,757	27,485,000
Balance at Sep. 30, 2019	$ 749,665	$ 124,155	$ 1,382,658	$ (10,238)	$ (746,910)