Investments (Schedule Of Unrealized Loss On Investments) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Market Value	$ 26,242	$ 7,126
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	100	145
Available-for-sale investments with unrealized losses, Fair Market Value, Total	26,242	7,126
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	100	145
Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Market Value		468
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss		18
Available-for-sale investments with unrealized losses, Fair Market Value, Total		468
Available-for-sale investments with unrealized losses, Unrealized Loss, Total		18
Corporate Bonds And Direct Obligations Of Government Agencies [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Market Value	14,956	6,067
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	97	126
Available-for-sale investments with unrealized losses, Fair Market Value, Total	14,956	6,067
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	97	126
U.S. Treasury Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale investments with unrealized losses, Less than 12 months, Fair Market Value	11,286	591
Available-for-sale investments with unrealized losses, Less than 12 months, Unrealized Loss	3	1
Available-for-sale investments with unrealized losses, Fair Market Value, Total	11,286	591
Available-for-sale investments with unrealized losses, Unrealized Loss, Total	$ 3	$ 1