Employee Benefit Plans - Schedule of Multi-Employer Pension Plans Affecting Period-to-Period Comparability of Contributions (Details) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2020 |
Dec. 31, 2019 |
Dec. 31, 2018 |
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| Retirement Benefits [Abstract] | |||
| Pension Fund | AI Pension Plan | ||
| Entity Tax Identification Number | 56-2010790 | ||
| Multiemployer Plan, Pension, Insignificant, Certified Zone Status [Fixed List] | Red | Red | |
| Sonic Contributions | $ 159 | $ 181 | $ 176 |
| Surcharge Imposed | Yes | ||
| Collective-Bargaining Agreement Expiration Date | BetweenOctober 2021and February 2022 | ||
| X | ||||||||||
- Definition The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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| X | ||||||||||
- Definition Indicates certified zone status of multiemployer pension plan determined to be individually insignificant. Acceptable values are "Green", "Yellow", "Orange", "Red", "Other", and "NA". Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Amount of cost for employer contribution to multiemployer pension plan determined to be individually insignificant. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
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| X | ||||||||||
- Definition Indicates whether employer paid surcharge to multiemployer pension plan determined to be individually insignificant. Acceptable values are "No", "Yes" and "NA". Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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| X | ||||||||||
- Definition Description of the significant collective-bargaining arrangements within the range of expiration dates for collective-bargaining arrangements requiring contributions to a multiemployer plan as well as other information to help investors understand the significance of the collective-bargaining agreements and when they expire. A multiemployer plan is 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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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| X | ||||||||||
- Definition Description of the general nature of multiemployer plans and of the employer's participation in those plans that would indicate how the risks of participating in these plans are different from single-employer plans. A multiemployer plan is 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. Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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