Investments: (Tables)

6 Months Ended

Jun. 30, 2012

Investments:

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

	June 30, 2012				December 31, 2011
	Cost		Fair Value		Cost		Fair Value
Equity securities	$	113,000	$	116,600	$	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

	June 30, 2012		December 31, 2011
Unrealized gains	$	3,600	$	32,900
Unrealized losses	—		(4,900		)
Net unrealized gains	$	3,600	$	28,000

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

	Three Months Ended				Six Months Ended
	June 30, 2012		June 25, 2011		June 30, 2012			June 25, 2011
Realized gains	$	—	$	—	$	42,300		$	—
Realized losses	—		—		(12,300		)	(600		)
Net realized gains/(losses)	$	—	$	—	$	30,000		$	(600	)