Goodwill Sensitivity Analysis, Percentage

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Number of internal divisions.

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Number Of Reporting Units At Risk After Cushion Test

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Amount of write-down of assets recognized in the income statement. Includes, but is not limited to, losses from tangible assets, intangible assets and goodwill.

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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.

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- Definition

Amount of loss from the write-down of an asset representing the future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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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.

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Sum of the carrying amounts of all intangible assets, excluding goodwill, as of the balance sheet date, net of accumulated amortization and impairment charges.

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Summary of Significant Accounting Policies - Goodwill (Details)	3 Months Ended			12 Months Ended
	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 USD ($) Reporting_Unit	Dec. 31, 2020 USD ($) division	Dec. 31, 2020 USD ($) Divisions	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Goodwill [Line Items]
Goodwill sensitivity analysis					10.00%
Number of reporting units at risk after cushion test \| Reporting_Unit						3
Number of internal divisions							2	2
Asset impairment charges				$ 8,282,000					$ 13,892,000	$ 49,375,000
Non-cash charge for impairment of goodwill	$ 0	$ 0	$ 0
Goodwill	2,121,014,000	2,022,675,000	1,899,879,000	2,121,014,000	$ 2,121,014,000	$ 2,121,014,000	$ 2,121,014,000	$ 2,121,014,000	2,022,675,000	1,899,879,000	$ 1,868,600,000
Intangible assets	435,655,000	413,734,000		435,655,000	435,655,000	$ 435,655,000	435,655,000	435,655,000	413,734,000
Underground Utility and Infrastructure Solutions
Goodwill [Line Items]
Number of reporting units at risk after cushion test \| Reporting_Unit						2
Goodwill	671,240,000	$ 657,512,000	$ 586,801,000	671,240,000	671,240,000	$ 671,240,000	671,240,000	671,240,000	$ 657,512,000	$ 586,801,000	$ 596,073,000
Underground Utility and Infrastructure Solutions \| Two Canadian Pipeline Operating Businesses And United State Material Handling Services
Goodwill [Line Items]
Goodwill	99,800,000			99,800,000	99,800,000	99,800,000	99,800,000	99,800,000
Intangible assets	19,500,000			19,500,000	19,500,000	19,500,000	19,500,000	19,500,000
Underground Utility and Infrastructure Solutions \| Specialized Industrial Services Business
Goodwill [Line Items]
Goodwill	303,000,000.0			303,000,000.0	303,000,000.0	303,000,000.0	303,000,000.0	303,000,000.0
Intangible assets	$ 53,300,000			$ 53,300,000	$ 53,300,000	$ 53,300,000	$ 53,300,000	$ 53,300,000