Fair Value Measurements. (Details) - USD ($) |
Sep. 30, 2021 |
Dec. 31, 2020 |
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| Fair Value Disclosures [Abstract] | ||
| Property and equipment held-for-sale at fair value | $ 20,535,000 | $ 48,548,000 |
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- Definition Fair value portion of assets classified as held for sale. Reference 1: http://www.xbrl.org/2003/role/exampleRef
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| X | ||||||||||
- References No definition available.
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