Earnings Per Share (Details 1) (USD $)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Stock appreciation rights were outstanding but not included in diluted earnings per share calculation
Options to purchase common stock (number of shares)	1,466,149	273,429	0
Price ranges per share		$ 46.78
Price ranges per share, minimum	$ 34.06
Price ranges per share, maximum	$ 46.78

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

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-Name Accounting Standards Codification

-Glossary Diluted Earnings Per Share

-URI http://asc.fasb.org/extlink&oid=6510752

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-Name Accounting Standards Codification

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-Name Accounting Standards Codification

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+ Details