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Receivables, Contract Liabilities and Performance Obligations - Additional Information (Detail) - USD ($) | 9 Months Ended
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Sep. 30, 2021 | Sep. 30, 2020
New Accounting Pronouncements And Changes In Accounting Principles [Abstract] |  |
Contract with customer, liability, revenue recognized |  | $ 53,454,000
Description of expected duration | With the exception of remaining performance obligations associated with our OneCall Support Services contracts which are included in the table above regardless of original duration, remaining performance obligations that have original expected durations of one year or less are not included in the table above. Amounts not included in the table above have an average original expected duration of nine months. |
Time and material contracts expected duration | 22 months |

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- Definition Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 8 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130549-203045 + Details
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- Definition Description of when remaining performance obligation is expected to be recognized as revenue. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 606 -SubTopic 10 -Section 50 -Paragraph 13 -Subparagraph (b)(2) -URI http://asc.fasb.org/extlink&oid=123351226&loc=SL49130556-203045 + Details
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