Investment in Leasing Operations: (Details 4) (Finance Leases Financing Receivable [Member], USD $)	6 Months Ended
	Jun. 28, 2014	Jun. 29, 2013
Finance Leases Financing Receivable [Member]
Activity in the allowance for credit losses for leasing operations
Balance at beginning of period	$ 822,700	$ 775,800
Provisions charged to expense	27,800	(37,900)
Recoveries	88,800	102,600
Deductions for amounts written-off		(17,300)
Balance at end of period	$ 939,300	$ 823,200