Calculation of Earnings Per Share - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Nov. 28, 2020	Nov. 30, 2019	Nov. 28, 2020	Nov. 30, 2019
Numerator for Basic and Diluted Earnings Per Share:
Net income (loss)	$ 689	$ (622)	$ (458)	$ (465)
Undistributed losses, Basic	(91)	(1,397)	(2,018)	(2,015)
Undistributed losses, Diluted	$ (91)	$ (1,397)	$ (2,018)	$ (2,015)
Denominator for Basic and Diluted Earnings Per Share:
Effect of dilutive securities dilutive stock options	17
Weighted Average Number of Shares Outstanding, Diluted	13,225	13,135	13,187	13,111
Basic
Numerator for Basic and Diluted Earnings Per Share:
Net income (loss)	$ 689	$ (622)	$ (458)	$ (465)
Diluted
Numerator for Basic and Diluted Earnings Per Share:
Net income (loss)	689	(622)	(458)	(465)
Common Stock
Numerator for Basic and Diluted Earnings Per Share:
Undistributed losses, Basic	(78)	(1,193)	(1,725)	(1,720)
Undistributed losses, Diluted	$ (78)	$ (1,193)	$ (1,725)	$ (1,720)
Denominator for Basic and Diluted Earnings Per Share:
Weighted Average Number of Shares Outstanding, Basic	11,111	11,038	11,090	11,014
Weighted Average Number of Shares Outstanding, Diluted	11,128	11,038	11,090	11,014
Net income (loss) per share:
Earnings Per Share, Basic	$ 0.05	$ (0.05)	$ (0.04)	$ (0.04)
Earnings Per Share, Diluted	$ 0.05	$ (0.05)	$ (0.04)	$ (0.04)
Common Stock | Basic
Numerator for Basic and Diluted Earnings Per Share:
Less dividends	$ 666	$ 662	$ 1,333	$ 1,324
Common Stock | Diluted
Numerator for Basic and Diluted Earnings Per Share:
Less dividends	666	662	1,333	1,324
Common Class B
Numerator for Basic and Diluted Earnings Per Share:
Undistributed losses, Basic	(13)	(204)	(293)	(295)
Undistributed losses, Diluted	$ (13)	$ (204)	$ (293)	$ (295)
Denominator for Basic and Diluted Earnings Per Share:
Weighted Average Number of Shares Outstanding, Basic	2,097	2,097	2,097	2,097
Weighted Average Number of Shares Outstanding, Diluted	2,097	2,097	2,097	2,097
Net income (loss) per share:
Earnings Per Share, Basic	$ 0.05	$ (0.04)	$ (0.03)	$ (0.03)
Earnings Per Share, Diluted	$ 0.05	$ (0.04)	$ (0.03)	$ (0.03)
Common Class B | Basic
Numerator for Basic and Diluted Earnings Per Share:
Less dividends	$ 114	$ 113	$ 227	$ 226
Common Class B | Diluted
Numerator for Basic and Diluted Earnings Per Share:
Less dividends	$ 114	$ 113	$ 227	$ 226