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Commitments and Contingencies - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified |
12 Months Ended | ||
|---|---|---|---|
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Dec. 31, 2013
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Dec. 31, 2012
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Dec. 31, 2011
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| Commitments and Contingencies Disclosure [Line Items] | |||
| Environmental accrual | $ 1.5 | $ 1.4 | |
| Capital lease obligations | 18.8 | 17.9 | |
| Capital lease obligations, maturity year | 2017 | ||
| Operating lease and rental contracts expenses | 7.5 | 7.8 | 0.6 |
| Asset retirement obligations | 2.8 | ||
| Surety Bonds | 5.2 | ||
| Agreed indemnity amount | 9.0 | ||
| Irrevocable letters of credit facilities outstanding | 3.1 | ||
| Available insurance limit | 16.0 | ||
| Purchase commitment | 13 | ||
| Remaining purchase commitment amount | $ 7.1 | ||
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Capital Lease Obligations
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| Commitments and Contingencies Disclosure [Line Items] | |||
| Capital lease obligations, interest rate | 3.30% | ||