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Benefit Plans - Additional Information (Detail) - USD ($) | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |
Employees eligibility | completed one year of service and are at least 21 years of age |  |
Minimum years of service required to participate in Company sponsored saving and profit sharing plan | 1 year |  |
Minimum age required to participate in Company sponsored saving and profit sharing plan | 21 years |  |
Employers contribution and compensation | match 50% of employees’ contributions up to 5% of eligible compensation |  |
Employers contribution as percentage of employees contribution | 50.00% |  |
Employers contribution as percentage of employees compensation | 5.00% |  |
Employees contribution limit | 100.00% |  |
Fully vesting period of contribution | 3 years |  |
Minimum age for entitlement to benefit of deferred compensation plan | 30 years |  |
Minimum years of experience to attain the benefit of deferred compensation plan | 10 years |  |
Deferred compensation arrangement with individual employees contribution minimum | $ 3,000 |  |
Deferred compensation arrangement with individual employees contribution maximum | 8,000 |  |
Deferred Profit Sharing [Member] |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |
Employer's contribution | 5,714,000 | $ 5,688,000 | $ 4,966,000
Deferred Compensation Plan [Member] |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |
Employer's contribution | 1,616,000 | $ 1,675,000 | $ 1,585,000
Benefit Plans [Member] |  |  |
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items] |  |  |
Letters of credit with bank | $ 8,228,000 |  |

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- Definition Deferred compensation arrangement with individual employees contribution minimum. + References No definition available. + Details
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- Definition Minimum age for entitlement to benefit of deferred compensation plan. + References No definition available. + Details
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- Definition Employees contribution limit. + References No definition available. + Details
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- Definition Minimum period the individual is required to perform services to be fully vested under the deferred compensation arrangement, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 710 -SubTopic 10 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=6409961&loc=d3e20487-108367 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(1) -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
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