Investment in Leasing Operations: Leasing Income (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 26, 2020	Sep. 28, 2019	Sep. 26, 2020	Sep. 28, 2019
Leasing income
Interest income on direct financing and sales-type leases	$ 839,600	$ 1,856,000	$ 2,947,900	$ 6,066,800
Selling profit (loss) at commencement of sales-type leases	267,700	1,098,100	1,453,600	1,971,600
Operating lease income	668,600	702,600	1,758,500	1,908,700
Income on sales of equipment under lease	913,400	496,600	5,078,300	2,268,500
Other	6,500	222,200	802,500	518,200
Leasing income	$ 2,695,800	$ 4,375,500	$ 12,040,800	$ 12,733,800