Business Combinations - Estimates of Acquired Intangible Assets (Detail) - USD ($) $ in Thousands	9 Months Ended
Sep. 30, 2020	Sep. 30, 2019
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 14,528	$ 8,566
Weighted Average Estimated Useful Life (yrs)	8 years	8 years
Trademarks and Trade Names [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 3,796	$ 2,615
Weighted Average Estimated Useful Life (yrs)	15 years	15 years
Covenants Not-to-Compete [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 1,946	$ 1,183
Weighted Average Estimated Useful Life (yrs)	5 years	5 years
Backlog [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Estimated Fair Value	$ 1,876
Weighted Average Estimated Useful Life (yrs)	1 year 6 months

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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- Definition

Weighted average amortization period of finite-lived intangible assets acquired either individually or as part of a group of assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(3)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

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- Definition

Amount of increase in assets, excluding financial assets, lacking physical substance with a definite life, from an acquisition.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 350
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16265-109275

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