Investments (Cost And Estimated Fair Value Of Investments) (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 5,341,000	$ 101,000
Gross unrealized gain	3,639,000	3,134,000
Gross unrealized losses	(55,000)	(54,000)
Fair value, investments	8,925,000	3,181,000
Less cash equivalents, Carrying amount	1,102,000	5,476,000	583,000
Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	804,000
Gross unrealized gain	0
Gross unrealized losses	0
Fair value, investments	804,000
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	200,000	5,373,000
Gross unrealized gain	0	0
Gross unrealized losses	0	0
Fair value, investments	200,000	5,373,000
Treasury Bills [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	5,249,000
Gross unrealized gain	0
Gross unrealized losses	(1,000)
Fair value, investments	5,248,000
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	92,000	101,000
Gross unrealized gain	3,639,000	3,134,000
Gross unrealized losses	(54,000)	(54,000)
Fair value, investments	3,677,000	3,181,000
Debt and Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	6,345,000	5,474,000
Gross unrealized gain	3,639,000	3,134,000
Gross unrealized losses	(55,000)	(54,000)
Fair value, investments	9,929,000	8,554,000
Less Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized gain	0	0
Gross unrealized losses	0	0
Less cash equivalents, Carrying amount	1,004,000	5,373,000
Less cash equivalents, Fair value	$ 1,004,000	$ 5,373,000