Income Taxes: (Detail) (USD $)	12 Months Ended
	Dec. 27, 2014	Dec. 28, 2013	Dec. 29, 2012
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 (35%)	$ 11,406,100	$ 10,356,500	$ 8,104,400
Valuation allowance	(25,800)	7,300	1,413,600
State and local income taxes, net of federal benefit	897,800	886,200	677,700
Permanent differences, including stock option expenses	144,500	113,000	60,200
Other, net	99,700	(4,700)	(38,300)
Income Tax Expense (Benefit), Total	12,522,300	11,358,300	10,217,600
Current provision for income taxes:
Federal	10,567,100	10,013,500	8,332,400
State	1,456,400	1,468,600	1,186,000
Foreign	386,900	375,400	374,900
Current provision	12,410,400	11,857,500	9,893,300
Deferred provision for income taxes:
Federal	134,200	(449,300)	435,300
State	(22,300)	(49,900)	(111,000)
Deferred provision	111,900	(499,200)	324,300
Income Tax Expense (Benefit), Total	12,522,300	11,358,300	10,217,600
Deferred tax assets:
Accounts receivable and lease reserves	169,600	376,900
Accrued restructuring charge	64,200	64,600
Non-qualified stock option expense	1,382,400	946,000
Deferred franchise and software license fees	720,900	606,600
Trademarks	91,100	95,600
Lease deposits	1,228,300	1,263,600
Loss from and impairment of equity and note investments	4,055,800	4,081,600
Valuation allowance	(4,055,800)	(4,081,600)
Other	420,100	328,200
Total deferred tax assets	4,076,600	3,681,500
Deferred tax liabilities:
Lease revenue and initial direct costs	(9,579,400)	(9,101,900)
Depreciation and amortization	(254,100)	(224,600)
Total deferred tax liabilities	(9,833,500)	(9,326,500)
Total net deferred tax liabilities	(5,756,900)	(5,645,000)
Excess tax benefits related to stock option exercises	91,100	413,600	884,300
Unrecognized tax benefits, including interest and penalties	465,500	398,000
Interest and penalties accrued related to unrecognized tax benefit	16,500	14,300
Activity related to the company's unrecognized tax benefits
Balance at the beginning of the period	383,700	312,300
Increases related to current year tax positions	136,500	111,500
Additions for tax positions of prior years	1,600	17,700
Expiration of the statute of limitations for the assessment of taxes	(72,800)	(57,800)
Balance at the end of the period	$ 449,000	$ 383,700	$ 312,300
Period over which various statutes of limitations are expected to expire	12 months