Nature of Business and Summary of Significant Accounting Policies - Net Income per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Mar. 31, 2021	Mar. 31, 2020
Nature of Business and Summary of Significant Accounting Policies
Basic EPS	$ 4,360	$ 3,615	$ 9,876	$ 10,420
Weighted average
Basic (in shares)	18,349,000	18,472,000	18,348,000	18,476,000
Diluted (in shares)	18,412,000	18,516,000	18,402,000	18,530,000
Effect of Dilutive Securities:
Stock Options	63,000	44,000	54,000	54,000
Diluted EPS	$ 4,360	$ 3,615	$ 9,876	$ 10,420
Basic (in dollars per share)	$ 0.24	$ 0.20	$ 0.54	$ 0.56
Diluted (in dollars per share)	$ 0.24	$ 0.20	$ 0.54	$ 0.56
Excluded from diluted EPS	8,000	44,000	27,000	27,000