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