Condensed Statements of Shareholder's Equity Condensed Statements of Shareholders' Equity (Unaudited) - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock [Member]	Common Stock [Member] Stock Options and Stock Appreciation Rights [ Member]	Common Stock [Member] Performance Shares [Member]	Common Stock [Member] Restricted Stock Units (RSUs) [Member]	Additional Paid-in Capital [Member]	Additional Paid-in Capital [Member] Stock Options and Stock Appreciation Rights [ Member]	Additional Paid-in Capital [Member] Performance Shares [Member]	Additional Paid-in Capital [Member] Restricted Stock Units (RSUs) [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Treasury Stock [Member] Stock Options and Stock Appreciation Rights [ Member]	Treasury Stock [Member] Performance Shares [Member]	Treasury Stock [Member] Restricted Stock Units (RSUs) [Member]	Total Accumulated Other Comprehensive Income (Loss) [Member]	Parent [Member]	Parent [Member] Stock Options and Stock Appreciation Rights [ Member]	Parent [Member] Performance Shares [Member]	Parent [Member] Restricted Stock Units (RSUs) [Member]
Beginning balance, shares at Jun. 30, 2018		38,703
Beginning balance at Jun. 30, 2018		$ 10,000				$ 169,383				$ 1,129,678	$ (403,875)				$ (90,223)	$ 814,963
Net income	$ 48,938															48,938
Other comprehensive (loss) income, net of tax	$ 5,347														5,347	5,347
Cumulative effect of adopting accounting standards | Adjustments for New Accounting Pronouncement [Member]										3,056						3,056
Cash dividends										(13)						(13)
Exercise of stock appreciation rights and options, shares			17
Performance share awards, shares				18
Restricted stock units, shares					16
Additional Paid in Capital, Exercise of stock appreciation rights and options, Performance share awards, Restricted stock units							$ (855)	$ (844)	$ (760)
Exercise of stock appreciation rights and options												$ (210)
Performance share awards													$ (301)
Restricted stock units														$ (198)
Total Shareholders' Equity, Exercise of stock appreciation rights and options, Performance share awards, Restricted stock units																	$ (1,065)	$ (1,145)	$ (958)
Compensation expense						1,043	651									1,043	651
Other										24	(35)					(11)
Ending balance, shares at Sep. 30, 2018		38,754
Ending balance at Sep. 30, 2018		$ 10,000				168,618				1,181,683	(404,619)				(84,876)	870,806
Beginning balance, shares at Jun. 30, 2019	38,597	38,597
Beginning balance at Jun. 30, 2019	$ 897,034	$ 10,000				172,931				1,229,148	(415,159)				(99,886)	897,034
Net income	38,799															38,799
Other comprehensive (loss) income, net of tax	$ (5,247)														(5,247)	(5,247)
Cumulative effect of adopting accounting standards | Adjustments for New Accounting Pronouncement [Member]										(3,275)						(3,275)
Cash dividends										(20)						(20)
Exercise of stock appreciation rights and options, shares			5
Performance share awards, shares				36
Restricted stock units, shares					16
Additional Paid in Capital, Exercise of stock appreciation rights and options, Performance share awards, Restricted stock units							(177)	$ (1,540)	$ (631)
Exercise of stock appreciation rights and options												$ 61
Performance share awards													$ 362
Restricted stock units														$ 200
Total Shareholders' Equity, Exercise of stock appreciation rights and options, Performance share awards, Restricted stock units																	(116)	$ (1,178)	$ (431)
Compensation expense						919	$ 773									919	$ 773
Stockholders' Equity, Other Shares		2
Other						(52)				(4)	23					(33)
Ending balance, shares at Sep. 30, 2019	38,655	38,656
Ending balance at Sep. 30, 2019	$ 927,225	$ 10,000				$ 172,223				$ 1,264,648	$ (414,513)				$ (105,133)	$ 927,225