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Employee Benefit Plans (Retiree Medical Coverage) - Additional Information (Detail) - USD ($) $ in Millions | 12 Months Ended |
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Dec. 31, 2019 | Dec. 31, 2018
Compensation And Retirement Disclosure [Abstract] |  |
Maximum number of years medical, dental and prescription drug coverage to spouses of retired former officers | 30 years |
Total liability recorded to provide medical, dental and prescription drug coverage | $ 0.1 | $ 0.1

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- Definition The maximum number of years medical, dental and prescription coverage is extended to the spouse of a former officer. + References No definition available. + Details
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- References No definition available. + Details
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- Definition The carrying amount of the liability as of the balance sheet date to an individual under a deferred compensation arrangement. This amount may be the result of periodic accruals made over the period of active employment, or reflect termination benefits resulting contractual terms or a death benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 710 -SubTopic 10 -Section 30 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6409875&loc=d3e20015-108363 + Details
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