Investment in Leasing Operations: (Details 4) (Investment in leases, USD $)	3 Months Ended
	Mar. 30, 2013	Mar. 31, 2012
Investment in leases
Activity in the allowance for credit losses for leasing operations
Balance at beginning of period	$ 775,800	$ 803,800
Provisions charged to expense	13,800	(53,000)
Recoveries	21,300	34,100
Deductions for amounts written-off	(10,900)	(25,700)
Balance at end of period	$ 800,000	$ 759,200