Long-Term Debt And Other Long-Term Liabilities (Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2011	Dec. 31, 2010
Long-Term Debt And Other Long-Term Liabilities
Credit agreement with average interest rates, of 2.2% and 3.5% at September 30, 2011 and December 31, 2010, respectively	$ 55,400	$ 163,000
6.625% senior subordinated notes due 2021	250,000	0
Total long-term debt	$ 305,400	$ 163,000
Revolving credit facility interest rate including the effect of hedging	2.20%	3.50%
Interest percentage of senior subordinated notes	6.625%
Debt instrument maturity date	2021