Goodwill and Intangible Assets - Summary of Changes in the Carrying Amount of Goodwill (Detail) - USD ($) $ in Thousands |
Sep. 30, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
|---|---|---|---|
| Goodwill and Intangible Assets Disclosure [Abstract] | |||
| Gross carrying amount | $ 9,393 | $ 9,393 | $ 9,393 |
| Accumulated impairment losses | 0 | 0 | |
| Net carrying value of goodwill | $ 9,393 | $ 9,393 | $ 9,393 |
| X | ||||||||||
- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- References No definition available.
|
| X | ||||||||||
- Definition Amount before accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Definition Amount of accumulated impairment loss for an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|