Summary of Significant Accounting Policies - Income per share (Details 1) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2022	Mar. 31, 2021
Numerator:
Net income per consolidated statements of income	$ 368	$ (702)	$ 1,603	$ 1,729	$ 1,869	$ 3,785	$ 1,267	$ 1,430	$ 2,998	$ 8,351
Percentage allocated to shareholders *									99.50%	99.50%
Numerator for basic and diluted earnings per share									$ 2,983	$ 8,307
Denominator:
Denominator for Basic earnings per share - weighted-average shares outstanding									7,572	7,626
Denominator for diluted earnings per share									7,572	7,626
Per share income from continuing operations
Basic	$ 0.05	$ (0.09)	$ 0.21	$ 0.22	$ 0.24	$ 0.49	$ 0.16	$ 0.18	$ 0.39	$ 1.09
Diluted	$ 0.05	$ (0.09)	$ 0.21	$ 0.22	$ 0.24	$ 0.49	$ 0.16	$ 0.18	$ 0.39	$ 1.09