CONDENSED CONSOLIDATED STATEMENT OF STOCKHOLDERS EQUITY - USD ($)	Common Stock	Additional Paid-in Capital	Treasury Stock	Retained Earnings	Total
Balance at Jun. 30, 2019	$ 212,000	$ 17,103,000	$ (17,067,000)	$ 70,924,000	$ 71,172,000
Balance (in shares) at Jun. 30, 2019	21,227,094		(2,749,310)
Net income	$ 0	0	$ 0	3,233,000	3,233,000
Stock-based compensation expense	0	17,000	0	0	17,000
Balance at Sep. 30, 2019	$ 212,000	17,120,000	$ (17,067,000)	74,157,000	74,422,000
Balance (in shares) at Sep. 30, 2019	21,227,094		(2,749,310)
Balance at Jun. 30, 2019	$ 212,000	17,103,000	$ (17,067,000)	70,924,000	71,172,000
Balance (in shares) at Jun. 30, 2019	21,227,094		(2,749,310)
Net income					6,805,000
Balance at Dec. 31, 2019	$ 212,000	17,428,000	$ (17,067,000)	77,729,000	78,302,000
Balance (in shares) at Dec. 31, 2019	21,227,094		(2,749,310)
Balance at Sep. 30, 2019	$ 212,000	17,120,000	$ (17,067,000)	74,157,000	74,422,000
Balance (in shares) at Sep. 30, 2019	21,227,094		(2,749,310)
Net income				3,572,000	3,572,000
Stock-based compensation expense		308,000			308,000
Balance at Dec. 31, 2019	$ 212,000	17,428,000	$ (17,067,000)	77,729,000	78,302,000
Balance (in shares) at Dec. 31, 2019	21,227,094		(2,749,310)
Balance at Jun. 30, 2020	$ 212,000	17,766,000	$ (19,521,000)	79,444,000	77,901,000
Balance (in shares) at Jun. 30, 2020	21,241,066		(2,893,715)
Net income	$ 0	0	$ 0	2,319,000	2,319,000
Stock-based compensation expense	0	104,000	0	0	104,000
Balance at Sep. 30, 2020	$ 212,000	17,870,000	$ (19,521,000)	81,763,000	80,324,000
Balance (in shares) at Sep. 30, 2020	21,241,066		(2,893,715)
Balance at Jun. 30, 2020	$ 212,000	17,766,000	$ (19,521,000)	79,444,000	77,901,000
Balance (in shares) at Jun. 30, 2020	21,241,066		(2,893,715)
Net income					5,516,000
Balance at Dec. 31, 2020	$ 212,000	17,954,000	$ (19,521,000)	84,960,000	83,605,000
Balance (in shares) at Dec. 31, 2020	21,241,066		(2,893,715)
Balance at Sep. 30, 2020	$ 212,000	17,870,000	$ (19,521,000)	81,763,000	80,324,000
Balance (in shares) at Sep. 30, 2020	21,241,066		(2,893,715)
Net income	$ 0	0	$ 0	3,197,000	3,197,000
Stock-based compensation expense	0	84,000	0	0	84,000
Balance at Dec. 31, 2020	$ 212,000	$ 17,954,000	$ (19,521,000)	$ 84,960,000	$ 83,605,000
Balance (in shares) at Dec. 31, 2020	21,241,066		(2,893,715)