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Line of Credit, Long-Term Debt and Finance Lease Obligations - Summary of Estimated Fair Value of Notes (Detail) - Level 2 [Member] - Estimate of Fair Value Measurement [Member] - USD ($) $ in Thousands | Dec. 31, 2020 | Dec. 31, 2019
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5.25% Senior Unsecured Notes Due 2023 [Member] |  |
Debt Instrument Fair Value [Line Items] |  |
Estimated fair value | $ 756,225 | $ 766,875
6.25% Senior Unsecured Notes Due 2027 [Member] |  |
Debt Instrument Fair Value [Line Items] |  |
Estimated fair value | $ 1,070,000 | $ 1,025,600

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- Definition Fair value portion of notes payable. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19,20,22) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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