Consolidated Statements Of Changes In Shareholders' Equity - USD ($) $ in Thousands	Total Par Value Of Common Shares [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive (Loss) Income [Member]	Total
Balance, period start at Jun. 30, 2016	$ 7,700	$ 23,259	$ 180,919	$ (2,228)	$ 209,650
Issuance of common stock:
Stock options exercised, net	79	999			1,078
Unrealized (gain) loss on available for sale investments, net of tax				36	36
Long-term incentive compensation	35	(213)			(178)
Stock-based compensation	8	647			655
Excess tax benefit from stock-based payment arrangements		1,494			1,494
Minimum pension liability adjustment, net of tax				479	479
Cash dividends declared			(6,240)		(6,240)
Net income (loss)			23,786		$ 23,786
Dividends declared per common share					$ 0.80
Balance, period end at Jun. 30, 2017	7,822	26,186	198,465	(1,713)	$ 230,760
Issuance of common stock:
Stock options exercised, net	17	216			233
Unrealized (gain) loss on available for sale investments, net of tax				(38)	(38)
Long-term incentive compensation	20	(858)			(838)
Stock-based compensation	9	777			786
Minimum pension liability adjustment, net of tax				41	41
Cash dividends declared			(6,912)		(6,912)
Net income (loss)			17,666		$ 17,666
Dividends declared per common share					$ 0.88
Balance, period end at Jun. 30, 2018	7,868	26,321	209,553	(2,044)	$ 241,698
Issuance of common stock:
ASU 2018-02 adoption			334	(334)
Stock options exercised, net	5	76			81
Unrealized (gain) loss on available for sale investments, net of tax				34	34
Long-term incentive compensation	7	(315)			(308)
Stock-based compensation	23	1,430			1,453
Minimum pension liability adjustment, net of tax				2,018	2,018
Cash dividends declared			(6,944)		(6,944)
Net income (loss)			(32,605)		$ (32,605)
Dividends declared per common share					$ 0.88
Balance, period end at Jun. 30, 2019	$ 7,903	$ 27,512	$ 170,004	$ 8	$ 205,427