Investments (Cost And Estimated Fair Value Of Investments) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 6,191	$ 6,614
Gross unrealized gain	4	1,238
Gross unrealized loss	(54)	(54)
Fair value, investments	6,141	7,798
Less cash equivalents, Carrying amount	2,435	1,190	$ 887	$ 1,505
Money Market [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	1,984	510
Gross unrealized gain	0	0
Gross unrealized loss	0	0
Fair value, investments	1,984	510
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	271	345
Gross unrealized gain	0	0
Gross unrealized loss	0	0
Fair value, investments	271	345
Treasury Bills [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	6,137	6,542
Gross unrealized gain	4	0
Gross unrealized loss	0	0
Fair value, investments	6,141	6,542
Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	54	72
Gross unrealized gain	0	1,238
Gross unrealized loss	(54)	(54)
Fair value, investments	0	1,256
Debt and Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	8,446	7,469
Gross unrealized gain	4	1,238
Gross unrealized loss	(54)	(54)
Fair value, investments	8,396	8,653
Less Cash and Cash Equivalents [Member]
Schedule of Available-for-sale Securities [Line Items]
Gross unrealized gain	0	0
Gross unrealized loss	0	0
Less cash equivalents, Carrying amount	2,255	855
Less cash equivalents, Fair value	$ 2,255	$ 855