Investments: (Tables)

9 Months Ended

Sep. 29, 2012

Investments:

Schedule of marketable securities classified as available-for-sale securities

	September 29, 2012				December 31, 2011
	Cost		Fair Value		Cost		Fair Value
Equity securities	$	92,400	$	90,400	$	1,015,800	$	1,043,800

Schedule of unrealized gains and losses for marketable securities classified as available-for-sale securities in accumulated other comprehensive income

	September 29, 2012			December 31, 2011
Unrealized gains	$	—		$	32,900
Unrealized losses	(2,000		)	(4,900		)
Net unrealized gains (losses)	$	(2,000	)	$	28,000

Schedule of realized gains and losses recognized on sales of available-for-sale marketable securities

	Three Months Ended				Nine Months Ended
	September 29,  2012		September 24, 2011		September 29,  2012			September 24,  2011
Realized gains	$	4,600	$	—	$	46,900		$	—
Realized losses	—		—		(12,300		)	(600		)
Net realized gains (losses)	$	4,600	$	—	$	34,600		$	(600	)