Long-Term Debt And Notes Payable (Components Of Debt) (Details) (USD $) In Thousands, unless otherwise specified			12 Months Ended			12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2011 5.50% Notes Due 2013 [Member]	Dec. 31, 2010 5.50% Notes Due 2013 [Member]	Sep. 30, 2003 5.50% Notes Due 2013 [Member]	Dec. 31, 2011 6.55% Notes Due 2036 [Member]	Dec. 31, 2010 6.55% Notes Due 2036 [Member]	Nov. 30, 2006 6.55% Notes Due 2036 [Member]
Debt Instrument [Line Items]
Total Long-term debt	$ 398,914	$ 398,736	$ 199,753	$ 199,608		$ 199,161	$ 199,128
Short-term borrowings	$ 1,112	$ 984
Debt instrument interest rate					5.50%			6.55%
Debt instrument due date			2013			2036