Investment in Leasing Operations: Credit Losses (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jul. 01, 2017	Jun. 30, 2018	Jul. 01, 2017	Dec. 30, 2017
Activity in the allowance for credit losses for leasing operations
Balance at beginning of period			$ 711,200	$ 896,000
Provision for credit losses	$ 109,000	$ (11,500)	204,000	(12,900)
Recoveries			(60,900)	10,200
Deductions for amounts written-off			(98,400)
Balance at end of period	755,900	$ 893,300	755,900	$ 893,300
Investment In Leases
Total investment in direct financing and sales-type leases	44,093,200		44,093,200		$ 41,974,200
Allowance for Credit Losses
Total	755,900		755,900		711,200
Investment in leases
Investment In Leases
Collectively evaluated for loss potential	44,093,200		44,093,200		41,974,200
Total investment in direct financing and sales-type leases	44,093,200		44,093,200		41,974,200
Allowance for Credit Losses
Collectively evaluated for loss potential	755,900		755,900		711,200
Total	$ 755,900		$ 755,900		$ 711,200