Employee Benefit Plans - Schedule of Multiemployer Plans (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Multiemployer Plans [Line Items]
Plan Number	001
Contribution by Entity	$ 4.0	$ 5.6	$ 6.0
Operating Engineers
Multiemployer Plans [Line Items]
EIN	946090764
Multiemployer Plan, Pension, Significant, Certified Zone Status [Fixed List]	Yellow
Multiemployer Plan, Pension, Significant, Funding Improvement or Rehabilitation Plan, Implementation Status [Fixed List]	Implemented
Contribution by Entity	$ 3.3	4.1	4.7
Multiemployer Plan, Pension, Significant, Surcharge [Fixed List]	No
Multiemployer Plan, Pension, Significant, Collective-Bargaining Arrangement, Expiration Date	Aug. 31, 2024
Laborers National
Multiemployer Plans [Line Items]
EIN	526074345
Multiemployer Plan, Pension, Significant, Certified Zone Status [Fixed List]	Yellow
Multiemployer Plan, Pension, Significant, Funding Improvement or Rehabilitation Plan, Implementation Status [Fixed List]	Implemented
Contribution by Entity	$ 0.2	0.2	0.2
Multiemployer Plan, Pension, Significant, Surcharge [Fixed List]	No
Multiemployer Plan, Pension, Significant, Collective-Bargaining Arrangement, Expiration Date	Aug. 31, 2021
Hawai‘i Laborers (GPRM)
Multiemployer Plans [Line Items]
EIN	996025107
Multiemployer Plan, Pension, Significant, Certified Zone Status [Fixed List]	Green
Multiemployer Plan, Pension, Significant, Funding Improvement or Rehabilitation Plan, Implementation Status [Fixed List]	No
Contribution by Entity	$ 0.3	1.1	0.9
Multiemployer Plan, Pension, Significant, Surcharge [Fixed List]	No
Hawai‘i Laborers (GPRS)
Multiemployer Plans [Line Items]
EIN	996025107
Multiemployer Plan, Pension, Significant, Certified Zone Status [Fixed List]	Green
Multiemployer Plan, Pension, Significant, Funding Improvement or Rehabilitation Plan, Implementation Status [Fixed List]	No
Contribution by Entity	$ 0.2	$ 0.2	$ 0.2
Multiemployer Plan, Pension, Significant, Surcharge [Fixed List]	No
Multiemployer Plan, Pension, Significant, Collective-Bargaining Arrangement, Expiration Date	Sep. 30, 2024

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.

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
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-Name Accounting Standards Codification
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Balance Type:	debit
Period Type:	duration

- Definition

Indicates certified zone status of multiemployer pension plan determined to be individually significant. Acceptable values are "Green", "Yellow", "Orange", "Red", "Other", and "NA".

+ References

+ Details

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- Definition

Expiration date of collective-bargaining arrangement (CBA) requiring contribution to multiemployer pension plan determined to be individually significant, in CCYY-MM-DD format.

+ References

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- Definition

Employer Identification Number (EIN) or Tax Identification Number (TIN) assigned by Internal Revenue Service (IRS) for multiemployer pension plan determined to be individually significant, in nine-digit numeric format.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 80
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-Paragraph 5
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- Definition

Indicates whether funding improvement plan or rehabilitation plan was implemented or pending for multiemployer pension plan, determined to be individually significant. Acceptable values are "No", "Pending", "Implemented", "Other", and "NA".

+ References

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- Definition

Plan number for multiemployer pension plan determined to be individually significant, in three-digit numeric format.

+ References

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- Definition

Indicates whether employer paid surcharge to multiemployer pension plan determined to be individually significant. Acceptable values are "No", "Yes" and "NA".

+ References

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- Definition

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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