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Multiemployer Plans - Narrative (Details)	12 Months Ended
	Dec. 31, 2020 USD ($) plan	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Multiemployer Plans [Line Items]
Withdrawal liability	$ 0	$ 0	$ 0
Minimum | Multiemployer Plans, Pension
Multiemployer Plans [Line Items]
Number of plans | plan	200
UNITED STATES | Multiemployer Plans, Pension
Multiemployer Plans [Line Items]
Contribution increase due to acquisition	$ 5,300,000
Contributions	204,082,000	215,478,000	190,229,000
UNITED STATES | Multiemployer Plans, Postretirement Benefit
Multiemployer Plans [Line Items]
Contribution increase due to acquisition	15,600,000
Contributions	156,100,000	$ 153,500,000	$ 135,900,000
UNITED STATES | Minimum | Multiemployer Plans, Pension
Multiemployer Plans [Line Items]
Contributions	2,000,000.0
Red Zone | UNITED STATES | Minimum | Multiemployer Plans, Pension
Multiemployer Plans [Line Items]
Contributions	500,000
Orange or Yellow Zones | UNITED STATES | Minimum | Multiemployer Plans, Pension
Multiemployer Plans [Line Items]
Contributions	$ 1,000,000.0

X

- Definition

Multiemployer Plans, Contribution Increase (Decrease), Acquisition

+ References

No definition available.

+ Details

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- Definition

Multiemployer Plans, Number of Plans

+ References

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- Definition

Amount of cost for employer contribution to multiemployer plan. Multiemployer plan includes, but is not limited to, pension plan determined to be individually significant and insignificant and other postretirement benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=35742348&loc=SL14450788-114948

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 35
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=29639808&loc=d3e29008-114946

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450702-114947

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 9
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450691-114947

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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.

+ References

No definition available.

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- Definition

Amount of the obligation recognized by withdrawing from a pension or postretirement benefit plan to which two or more unrelated employers contribute where assets contributed by one participating employer may be used to provide benefits to employees of other participating employers.

+ References

No definition available.

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