Stock Compensation Plans - Stock options activity (Details) - shares	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017	Dec. 31, 2016
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Option, Granted	0	0	0
Option, Outstanding	20,000	35,000	44,250	72,375
Incentive Stock Options [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Option, Granted	0	0	0
Option, Outstanding	20,000	20,000	29,250
Director Stock Options [Member]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Option, Granted	0	0	0
Option, Outstanding	0	15,000	15,000