Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Jun. 30, 2018	8,656,677			1,098,268
Balance at Jun. 30, 2018	$ 85	$ 24,486	$ 50,839	$ (6,584)	$ (578)	$ 68,248
Issuance of common stock for restricted stock grants (in shares)	15,000
Issuance of common stock for restricted stock grants
Compensation expense related to stock compensation plans		1,299				1,299
Repurchase of common stock (in shares)				44,487
Repurchase of common stock				$ (430)		(430)
Unrealized gain (loss) resulting from change in fair value of derivative instruments, net of tax					1,235	1,235
Net income			4,740			4,740
Forfeiture of restricted stock (in shares)				5,000
Forfeiture of restricted stock
Issuance of common stock for stock option exercise (in shares)	5,000					5,000
Issuance of common stock for stock option exercise		38				$ 38
Balance (in shares) at Dec. 31, 2018	8,676,677			1,147,755
Balance at Dec. 31, 2018	$ 85	25,823	55,579	$ (7,014)	657	75,130
Balance (in shares) at Sep. 30, 2018	8,676,677			1,098,942
Balance at Sep. 30, 2018	$ 85	25,177	53,398	$ (6,590)	(195)	71,876
Compensation expense related to stock compensation plans		646				646
Repurchase of common stock (in shares)				43,813
Repurchase of common stock				$ (424)		(424)
Unrealized gain (loss) resulting from change in fair value of derivative instruments, net of tax					852	852
Net income			2,180			2,181
Forfeiture of restricted stock (in shares)				5,000
Forfeiture of restricted stock
Issuance of common stock for stock option exercise (in shares)						0
Balance (in shares) at Dec. 31, 2018	8,676,677			1,147,755
Balance at Dec. 31, 2018	$ 85	25,823	55,579	$ (7,014)	657	$ 75,130
Balance (in shares) at Jun. 30, 2019	8,851,677			1,626,605
Balance at Jun. 30, 2019	$ 87	26,280	57,380	$ (7,955)	292	76,084
Issuance of common stock for restricted stock grants (in shares)	5,000
Issuance of common stock for restricted stock grants
Compensation expense related to stock compensation plans		892				892
Repurchase of common stock (in shares)				159,668
Repurchase of common stock				$ (1,332)		(1,332)
Unrealized gain (loss) resulting from change in fair value of derivative instruments, net of tax					(516)	(516)
Net income			572			572
Forfeiture of restricted stock (in shares)				15,000
Forfeiture of restricted stock
Cumulative-effect adjustment pursuant to adoption of ASU 2016-02 (Note E) | Accounting Standards Update 2016-02 [Member]			420			420
Tax Cuts and Jobs Act, Reclassification from AOCI to Retained Earnings, Tax Effect | Accounting Standards Update 2018-02 [Member]			128		(128)
Tax Cuts and Jobs Act, Reclassification from AOCI to Retained Earnings, Tax Effect					(128)
Issuance of common stock for stock option exercise (in shares)						0
Balance (in shares) at Dec. 31, 2019	8,856,677			1,801,273
Balance at Dec. 31, 2019	$ 87	27,172	58,500	$ (9,287)	(352)	$ 76,120
Balance (in shares) at Sep. 30, 2019	8,851,677			1,643,322
Balance at Sep. 30, 2019	$ 87	26,713	58,024	$ (7,970)	551	77,405
Issuance of common stock for restricted stock grants (in shares)	5,000
Issuance of common stock for restricted stock grants
Compensation expense related to stock compensation plans		459				459
Repurchase of common stock (in shares)				157,951
Repurchase of common stock				$ (1,317)		(1,317)
Unrealized gain (loss) resulting from change in fair value of derivative instruments, net of tax					(903)	(903)
Net income			476			$ 476
Tax Cuts and Jobs Act, Reclassification from AOCI to Retained Earnings, Tax Effect
Issuance of common stock for stock option exercise (in shares)						0
Balance (in shares) at Dec. 31, 2019	8,856,677			1,801,273
Balance at Dec. 31, 2019	$ 87	$ 27,172	$ 58,500	$ (9,287)	$ (352)	$ 76,120