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Employee Benefit Plans - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) Employees	Mar. 31, 2018	Dec. 31, 2017 USD ($)	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016 USD ($)	Jun. 30, 2016	Mar. 31, 2016
Multiemployer Plans, Pension [Member]
Number Of Local Unions | Employees	100
Multiemployer Plans Red Zone Funded Status Percentage	65.00%
Multiemployer Plans Green Zone Funded Status Percentage	80.00%
Multiemployer Plans, Pension [Member] | Maximum [Member]
Multiemployer Plans Yellow Zone Funded status Percentage	80.00%
Multiemployer Plans, Pension [Member] | Minimum [Member]
Multiemployer Plans Yellow Zone Funded status Percentage	65.00%
Eighth District Electrical Pension Fund [Member] | Multiemployer Plans, Pension [Member]
Multiemployer Plan, Collective-Bargaining Arrangement, Required Percentage of Contributions		5.00%			5.00%			5.00%
IBEW Local 769 Management Pension Plan A [Member] | Multiemployer Plans, Pension [Member]
Multiemployer Plan, Collective-Bargaining Arrangement, Required Percentage of Contributions				5.00%			5.00%
Other Postretirement Benefits Plan [Member] | Foreign Plan [Member] | Retirement Saving Plan [Member]
Defined Contribution Plan, Cost	$ 0.1		$ 0.1
Other Postretirement Benefits Plan [Member] | UNITED STATES | Profit Sharing And Thrift Employee Benefit Plan [Member]
Defined Contribution Plan, Cost	4.7		3.4			$ 4.6
Other Postretirement Benefits Plan [Member] | UNITED STATES | Employee Benefit Plan [Member]
Defined Contribution Plan, Cost	$ 1.0		$ 0.6			$ 0.6

X

- Definition

Represents the percentage funded for green zone status.

+ References

No definition available.

+ Details

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X

- Definition

Represents the percentage funded for red zone status.

+ References

No definition available.

+ Details

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X

- Definition

Represents the percentage funded for yellow zone status.

+ References

No definition available.

+ Details

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X

- Definition

Represents the number of local unions.

+ References

No definition available.

+ Details

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X

- Definition

Amount of cost for defined contribution plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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X

- Definition

Percentage of contributions required by collective bargaining arrangement to all contributions required of employer for pension and other postretirement 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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947

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- Details

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