EMPLOYEE BENEFIT PLANS Employer plans (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018
Participation in the multiemployer pension plans
Contributions by Global Power	$ 10,221	$ 9,233
Boilermaker-Blacksmith National Pension Trust
Participation in the multiemployer pension plans
EIN/Pension Plan Number	48-6168020
Multiemployer Plans, Certified Zone Status	Other	Other
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	Implemented
Contributions by Global Power	$ 2,139	$ 2,117
Multiemployer Plans, Surcharge	No
Central Pension Fund of the IUOE and Participating Employers
Participation in the multiemployer pension plans
EIN/Pension Plan Number	36-6052390
Multiemployer Plans, Certified Zone Status	Green	Green
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	No
Contributions by Global Power	$ 280	$ 105
Central States, Southeast, and Southwest Pension Fund
Participation in the multiemployer pension plans
EIN/Pension Plan Number	36-6044243
Multiemployer Plans, Certified Zone Status	Other	Other
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	Implemented
Contributions by Global Power	$ 70	$ 65
Multiemployer Plans, Surcharge	No
Excavators Union Local 731 Pension Fund
Participation in the multiemployer pension plans
EIN/Pension Plan Number	13-1809825
Multiemployer Plans, Certified Zone Status	Green	Green
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	No
Contributions by Global Power	$ 303	$ 385
Multiemployer Plans, Collective-Bargaining Arrangement, Expiration Date	Apr. 30, 2022
IBEW Local 1579 Pension Plan
Participation in the multiemployer pension plans
EIN/Pension Plan Number	58-1254974
Multiemployer Plans, Certified Zone Status	Other	Other
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	No
Contributions by Global Power	$ 385	$ 123
Multiemployer Plans, Collective-Bargaining Arrangement, Expiration Date	Jul. 31, 2020
Iron Workers District Council of Tennessee Valley & Vicinity Pension Plan
Participation in the multiemployer pension plans
EIN/Pension Plan Number	62-6098036
Multiemployer Plans, Certified Zone Status	Green	Green
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	No
Contributions by Global Power	$ 250	$ 128
IUPAT Industry Pension Plan
Participation in the multiemployer pension plans
EIN/Pension Plan Number	52-6073909
Multiemployer Plans, Certified Zone Status	Other	Other
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	Implemented
Contributions by Global Power	$ 1,853	$ 2,061
Laborers National Pension Fund
Participation in the multiemployer pension plans
EIN/Pension Plan Number	75-1280827
Multiemployer Plans, Certified Zone Status	Other	Other
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	No
Contributions by Global Power	$ 176	$ 111
National Asbestos Workers Pension Plan
Participation in the multiemployer pension plans
EIN/Pension Plan Number	52-6038497
Multiemployer Plans, Certified Zone Status	Other	Other
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	Implemented
Contributions by Global Power	$ 1,288	$ 1,315
Multiemployer Plans, Surcharge	No
National Electrical Benefits Fund
Participation in the multiemployer pension plans
EIN/Pension Plan Number	53-0181657
Multiemployer Plans, Certified Zone Status	Green	Green
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	No
Contributions by Global Power	$ 308	$ 203
Plumbers & Pipefitters National Pension Fund
Participation in the multiemployer pension plans
EIN/Pension Plan Number	52-6152779
Multiemployer Plans, Certified Zone Status	Other	Other
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	Implemented
Contributions by Global Power	$ 284	$ 244
Plumber and Steamfitters Local Union No. 43 Pension Fund
Participation in the multiemployer pension plans
EIN/Pension Plan Number	62-6101288
Multiemployer Plans, Certified Zone Status	Green	Green
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	No
Contributions by Global Power	$ 162	$ 117
Sheet Metal Workers' National Pension Fund
Participation in the multiemployer pension plans
EIN/Pension Plan Number	52-6112463
Multiemployer Plans, Certified Zone Status	Other	Other
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	Implemented
Contributions by Global Power	$ 204	$ 354
Southern Ironworkers Pension Plan
Participation in the multiemployer pension plans
EIN/Pension Plan Number	59-6227091
Multiemployer Plans, Certified Zone Status	Green	Green
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	No
Contributions by Global Power	$ 260	$ 111
Multiemployer Plans, Collective-Bargaining Arrangement, Expiration Date	Jul. 31, 2020
Tri-State Carpenters & Joiners Pension Trust Fund
Participation in the multiemployer pension plans
EIN/Pension Plan Number	62-0976048
Multiemployer Plans, Certified Zone Status	Other	Other
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	Implemented
Contributions by Global Power	$ 322	$ 238
Multiemployer Plans, Surcharge	No
Washington State Plumbing and Pipefitting Industry Pension Plan
Participation in the multiemployer pension plans
EIN/Pension Plan Number	91-6029141
Multiemployer Plans, Certified Zone Status	Green	Green
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	No
Contributions by Global Power	$ 99	$ 69
Washington-Idaho Laborers-Employers Pension Trust
Participation in the multiemployer pension plans
EIN/Pension Plan Number	91-6123988
Multiemployer Plans, Certified Zone Status	Green	Green
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	No
Contributions by Global Power	$ 153	$ 74
Washington-Idaho-Montana Carpenters-Employers Retirement Fund
Participation in the multiemployer pension plans
EIN/Pension Plan Number	91-6123987
Multiemployer Plans, Certified Zone Status	Other	Other
Multiemployer Plans, Funding Improvement Plan and Rehabilitation Plan	Implemented
Contributions by Global Power	$ 287	$ 77
All Others
Participation in the multiemployer pension plans
Contributions by Global Power	$ 1,399	$ 1,335
Minimum
Participation in the multiemployer pension plans
Individual union CBA range	1 year
Maximum
Participation in the multiemployer pension plans
Individual union CBA range	3 years

The Tax Identification Number (TIN), also known as an Employer Identification Number (EIN), is a unique 9-digit value assigned by the IRS.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation 12B
-Number 240
-Section 12
-Subsection b-2

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Indicate the multiemployer plan's certified zone status as currently required by the Pension Protection Act of 2006 or a subsequent amendment thereof. The zone status categories are red (critical status), orange (seriously endangered), yellow (endangered), and green (none of the above). The acceptable values are "red", "orange", "yellow", "green", "other", and "NA". A multiemployer plan is 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

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 (c)
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Expiration date of the collective bargaining arrangement requiring contributions to the multiemployer plan, in CCYY-MM-DD format. A multiemployer plan is 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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 80
-Section 50
-Paragraph 5
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Indicate whether a funding improvement plan or rehabilitation plan has been implemented or is pending for 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. The acceptable values are "no", "pending", "implemented", "other", and "NA".

+ References

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-Section 50
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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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No definition available.

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Amount of contributions made to multiemployer plan by all employers who participate in plan.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 80
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-Paragraph 7
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Indicate whether the employer paid a surcharge to the 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. The acceptable values are "no", "yes", and "NA".

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (f)(2)
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Expiration range of the collective bargaining arrangement requiring contributions to the multiemployer plan

+ References

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