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Nature of Operations and Significant Accounting Policies - Additional Information (Detail) (USD $)
In Millions, except Share data, unless otherwise specified |
3 Months Ended | 9 Months Ended | |||
|---|---|---|---|---|---|
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Sep. 30, 2012
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Sep. 30, 2012
Immaterial Correction Of Error Pension Before Tax
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Sep. 30, 2012
Immaterial Correction Of Error Pension After Tax
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Sep. 30, 2012
Immaterial Correction Of Error Operating Activities
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Sep. 30, 2012
Immaterial Correction Of Error Financing Activities
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| Reclassification from other assets to treasury stock, Amount | $ 6.2 | ||||
| Reclassification from other assets to treasury stock, Shares | 188,621 | ||||
| Decrease to cash flows from operating activities due to identification of errors reported in cash flow | $ 2.0 | $ 1.3 | $ 4.4 | $ 4.4 | |