Senior Notes (Schedule Of Outstanding Senior Notes) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	5.40%	5.40%
Date due	Oct. 15, 2014	Oct. 15, 2014
5.40% Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument, stated interest rate	5.40%
Date issued	Oct. 12, 2004
Date due	Oct. 15, 2014
Principal amounts	$ 250,000,000
Consolidated balance sheet amount	249,958,000	249,907,000
Market value	$ 259,130,000	$ 266,390,000