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Employee Benefit Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified | 12 Months Ended
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Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items] |  |  |
Partial withdrawal liability | $ 32.6 | $ 32.6 |
Multiemployer defined contribution plan contributions | 87.0 | 46.7 | 35.8
Four Zero One K Plan [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of contribution by employer of each employee's contribution up to 3% | 100.00% |  |
Percentage of contribution by employer of each employee who contributes between three and six percent | 50.00% |  |
Percentage of employee contribution, lower range | 3.00% |  |
Percentage of employee contribution, high range | 6.00% |  |
Contributions to all non union defined contribution plans | $ 11.0 | $ 9.5 | $ 8.9
Red Zone [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage Funded in this Zone | Less than 65% |  |
Yellow Zone [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage Funded in this Zone | Less than 80% |  |
Green Zone [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage Funded in this Zone | at least 80% |  |

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- Definition Multiemployer defined contribution plan period contributions. + References No definition available. + Details
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- Definition Percentage Funded In This Zone + References No definition available. + Details
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- Definition Percentage of contribution by employer of each employee contribution up to specific percentage. + References No definition available. + Details
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- Definition Percentage of contribution by employer of each employee who contributes between three and six percent. + References No definition available. + Details
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- Definition Percentage of employee contribution, high range. + References No definition available. + Details
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- Definition Percentage of employee contribution, low range. + References No definition available. + Details
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- Details
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- Definition The amount of the cost recognized during the period for defined contribution plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6414718&loc=d3e28014-114942 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 11 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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- Definition Amount of the obligation recognized by withdrawing from a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers. + References No definition available. + Details
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