Income Taxes: Reconciliation, Components and Deferred Taxes (Details) - USD ($)	12 Months Ended
	Dec. 28, 2019	Dec. 29, 2018	Dec. 30, 2017
Income Taxes:
Federal statutory tax rate (as a percent)	21.00%	21.00%	35.00%
Reconciliation of the expected federal income tax expense based on the federal statutory tax rate to the actual income tax expense
Federal income tax expense at statutory rate (21%, 21%, 35%)	$ 8,708,200	$ 8,249,400	$ 12,758,000
Change in valuation allowance	147,900	(13,800)	7,500
State and local income taxes, net of federal benefit	1,310,800	1,334,100	1,057,100
Permanent differences, including stock option expenses	(1,056,800)	(355,500)	(628,400)
Adjustment to uncertain tax positions	(58,500)	4,500	77,800
Rate change			(1,540,300)
Other, net	266,500	(61,100)	139,300
Total provision for income taxes	9,318,100	9,157,600	11,871,000
Current provision for income taxes:
Federal	9,076,400	6,355,800	10,296,100
State	1,693,800	1,551,000	1,688,100
Foreign	363,200	423,000	365,900
Current provision	11,133,400	8,329,800	12,350,100
Deferred provision for income taxes:
Federal	(1,834,800)	967,300	(463,800)
State	19,500	(139,500)	(15,300)
Deferred provision	(1,815,300)	827,800	(479,100)
Total provision for income taxes	9,318,100	9,157,600	$ 11,871,000
Deferred tax assets:
Accounts receivable and lease reserves	154,700	215,900
Non-qualified stock option expense	1,758,100	2,071,600
Deferred revenue	1,957,500	2,020,100
Trademarks	34,500	39,800
Lease deposits	930,700	1,004,700
Loss from and impairment of equity and note investments	2,595,500	2,620,700
Foreign tax credits	173,100
Valuation allowance	(2,768,600)	(2,620,700)
Other	194,400	331,400
Total deferred tax assets	5,029,900	5,683,500
Deferred tax liabilities:
Lease revenue and initial direct costs	(4,207,400)	(6,664,800)
Depreciation and amortization	(155,500)	(167,000)
Total deferred tax liabilities	(4,362,900)	(6,831,800)
Total net deferred tax liabilities		$ (1,148,300)
Total net deferred tax liabilities	$ 667,000