The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

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Indicates certified zone status of multiemployer pension plan determined to be individually significant. Acceptable values are "Green", "Yellow", "Orange", "Red", "Other", and "NA".

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Expiration date of collective-bargaining arrangement (CBA) requiring contribution to multiemployer pension plan determined to be individually significant, in CCYY-MM-DD format.

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Amount of cost for employer contribution to multiemployer pension plan determined to be individually significant.

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Indicates whether funding improvement plan or rehabilitation plan was implemented or pending for multiemployer pension plan, determined to be individually significant. Acceptable values are "No", "Pending", "Implemented", "Other", and "NA".

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Indicates whether employer paid surcharge to multiemployer pension plan determined to be individually significant. Acceptable values are "No", "Yes" and "NA".

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Multiemployer Pension Plans - Multiemployer Pension Plan Description and Contributions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Multiemployer Pension Plan Disclosure [Line Items]
Entity Tax Identification Number	94-3030279
Contributions of the Company	$ 4.9	$ 5.0	$ 4.7
USW Plan
Multiemployer Pension Plan Disclosure [Line Items]
Entity Tax Identification Number	23-6648508
Pension Protection Act Zone Status	Green	Green
FIP/RP Status Pending/Implemented in 2020	No
Contributions of the Company	$ 3.8	$ 3.8	3.6
Surcharge Imposed in 2020	No
USW Plan \| Minimum
Multiemployer Pension Plan Disclosure [Line Items]
Expiration Date of Collective-Bargaining Agreement	Mar. 31, 2021
USW Plan \| Maximum
Multiemployer Pension Plan Disclosure [Line Items]
Expiration Date of Collective-Bargaining Agreement	Sep. 30, 2025
Other Funds
Multiemployer Pension Plan Disclosure [Line Items]
Contributions of the Company	$ 1.1	$ 1.2	$ 1.1