Long-Term Debt And Other Long-Term Liabilities (Long-Term Debt) (Details) (USD $)			9 Months Ended
	Sep. 30, 2012	Dec. 31, 2011	Sep. 30, 2012 6.625% Senior Subordinated Notes Due 2021 [Member]	May 18, 2011 6.625% Senior Subordinated Notes Due 2021 [Member]
Debt Instrument [Line Items]
Outstanding Borrowings Subject To LIBOR	$ 0
Credit agreement with an average interest rate of 2.7% at December 31, 2011		50,000,000
6.625% senior subordinated notes due 2021	645,154,000	250,000,000
Long-term debt (Note 6)	$ 645,154,000	$ 300,000,000
Revolving credit facility interest rate	0.00%	2.70%
Interest percentage of senior subordinated notes			6.625%	6.625%
Debt instrument maturity date			May 15, 2021