EMPLOYEE BENEFIT PLANS - Contributions in Multiemployer Pension Plans (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Contribution Plan Disclosure [Line Items]
Contributions by the Company	$ 965	$ 1,020	$ 1,306
Contribution to the plan (as a percent)	5.00%
Idaho Operating Engineers Employers Pension Trust Fund
Defined Contribution Plan Disclosure [Line Items]
EIN	916075538
Plan Number	001
Pension Protection Act Zone Status		Green	Green
FIP / RP Status Pending / Implemented	No
Contributions by the Company	$ 965	$ 1,020	$ 1,306
Surcharge Imposed	No
Expiration Dates of Collective Bargaining Agreements	Aug. 06, 2021
Automobile Mechanics Local Number Seven Hundred And One Union and Industry Pension Plan
Defined Contribution Plan Disclosure [Line Items]
EIN	366042061
FIP / RP Status Pending / Implemented	Implemented
Surcharge Imposed	Yes

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

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-Name Regulation 12B
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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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Amount of contributions made to multiemployer plan by employer.

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-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
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Three digit plan number 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.

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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.

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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.

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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".

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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".

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Defined contribution plan percentage of contribution.

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