Consolidated Statements Of Changes In Shareholders' Equity - USD ($) $ in Thousands	Total Par Value Of Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Jun. 30, 2014	$ 7,371	$ 15,386	$ 145,234	$ (1,256)	$ 166,735
Issuance of common stock:
Stock options exercised, net	83	707			790
Unrealized gain on available for sale investments, net of tax				(147)	(147)
Long-term incentive compensation	26	1,310			1,336
Stock-based compensation		607			607
Excess tax benefit from stock-based payment arrangements		(817)			(817)
Minimum pension liability adjustment, net of tax				(333)	(333)
Cash dividends declared			(5,357)		(5,357)
Net income			22,299		22,299
Balance at Jun. 30, 2015	7,480	18,827	162,176	(1,736)	$ 186,747
Issuance of common stock:
Common Stock, Dividends, Per Share, Declared					$ 0.72
Balance at Jun. 30, 2014	7,371	15,386	145,234	(1,256)	$ 166,735
Issuance of common stock:
Excess tax benefit from stock-based payment arrangements					0
Balance at Jun. 30, 2017	7,822	26,186	198,465	(1,713)	230,760
Balance at Jun. 30, 2015	7,480	18,827	162,176	(1,736)	186,747
Issuance of common stock:
Stock options exercised, net	184	1,407			1,591
Unrealized gain on available for sale investments, net of tax				128	128
Long-term incentive compensation	27	858			885
Stock-based compensation	9	406			415
Excess tax benefit from stock-based payment arrangements		1,761			1,761
Minimum pension liability adjustment, net of tax				(620)	(620)
Cash dividends declared			(5,494)		(5,494)
Net income			24,237		24,237
Balance at Jun. 30, 2016	7,700	23,259	180,919	(2,228)	$ 209,650
Issuance of common stock:
Common Stock, Dividends, Per Share, Declared					$ 0.72
Stock options exercised, net	79	999			$ 1,078
Unrealized gain 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			23,786		23,786
Balance at Jun. 30, 2017	$ 7,822	$ 26,186	$ 198,465	$ (1,713)	$ 230,760
Issuance of common stock:
Common Stock, Dividends, Per Share, Declared					$ 0.80