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Supplemental Disclosures of Cash Flow Information - Additional Information (Detail) - Qualified Contributory Savings and Thrift 401(k) Plan [Member] - USD ($) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2021 | Jun. 30, 2021 | Jun. 30, 2020
Defined Benefit Plan Disclosure [Line Items] |  |  |
Matching contributions by employer, percentage |  | 100.00% |
Percentage of eligible compensation for matching contributions by employer | 5.00% | 5.00% |
Matching contributions vesting schedule |  | 5 years |
Contribution expense to plan |  | $ 34.5 | $ 30.3

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- Definition Defined benefit plan percentage of eligible compensation for matching contributions by employer. + References No definition available. + Details
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- Definition Matching contributions vesting schedule. + References No definition available. + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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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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- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
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- Details
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