Investments: (Tables)

3 Months Ended

Mar. 30, 2013

Investments:

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

	March 30, 2013				December 29, 2012
	Cost		Fair Value		Cost		Fair Value
Equity securities	$	92,400	$	89,300	$	92,400	$	85,900

Schedule of the Company's unrealized gains and losses for marketable securities classified as available-for-sale securities in accumulated other comprehensive loss

	March 30, 2013			December 29, 2012
Unrealized gains	$	1,000		$	—
Unrealized losses	(4,100		)	(6,500		)
Net unrealized losses	$	(3,100	)	$	(6,500	)

Schedule of the Company's realized gains and losses recognized on sales of available-for-sale marketable securities

	Three Months Ended
	March 30, 2013		March 31, 2012
Realized gains	$	—	$	42,300
Realized losses	—		(12,300		)
Net realized gains	$	—	$	30,000