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Employee Benefit Plans - Additional Information (Details) $ in Millions | 12 Months Ended
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Dec. 31, 2020 USD ($) union | Dec. 31, 2019 USD ($) | Dec. 31, 2018 USD ($)
Multiemployer Plans, Pension |  |  |
Number of local unions (union) | union | 300 |  |
United States | Profit Sharing and Thrift Employee Benefit Plan | Other Postretirement Benefits Plan |  |  |
Contributions to benefit plans | $ | $ 16.8 | $ 10.9 | $ 5.8

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- Definition Amount of cost for defined contribution plan. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 + Details
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