Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Earnings Per Share
Net income (loss)	$ 232	$ 10,477	$ (241,406)	$ (176,117)
Shares of common stock and common stock equivalents:
Average common shares used in basic computation	38,301	40,615	38,672	41,051
Effect of dilutive securities (in shares)	951	656
Average common shares used in diluted computation	39,252	41,271	38,672	41,051
Earnings per share:
Basic (in dollars per share)	$ 0.01	$ 0.26	$ (6.24)	$ (4.29)
Diluted (in dollars per share)	$ 0.01	$ 0.25	$ (6.24)	$ (4.29)
Anti-dilutive equity awards not included in the detailed earnings per share computation
Equity awards not included in the detailed earnings per share computation	672	1,451	1,608	2,233

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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