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 12b
-Subsection 1

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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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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 5
-Subparagraph (b)
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Amount of contributions made to multiemployer plans by the employer. 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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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 80
-Section 50
-Paragraph 11
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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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-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.

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-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".

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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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Defined contribution plans increase decrease in contribution rate.

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Multiemployer plans, surcharge imposed.

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Percentage of funds required in the critical status

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EMPLOYEE BENEFIT PLANS - Contributions in Multiemployer Pension Plans (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Defined Contribution Plan Disclosure [Line Items]
Contributions by the Company	$ 2,584,000	$ 2,405,000	$ 2,678,000
Percentage of contribution to the plan	5.00%
Increasing in weekly pension fund contribution rates	$ 75
Surcharge imposed	5.00%
Defined Contribution Plan
Defined Contribution Plan Disclosure [Line Items]
Surcharge imposed	10.00%
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	$ 1,820,000	1,745,000	$ 2,154,000
Surcharge Imposed	No
Expiration Dates of Collective Bargaining Agreements	Jun. 30, 2018
Automobile Mechanics Local Number Seven Hundred And One Union and Industry Pension Plan
Defined Contribution Plan Disclosure [Line Items]
EIN	366042061
Plan Number	001
Pension Protection Act Zone Status			Red	Red
FIP / RP Status Pending / Implemented	Implemented
Contributions by the Company	$ 764,000	$ 660,000	$ 524,000
Surcharge Imposed	Yes
Expiration Dates of Collective Bargaining Agreements	Dec. 11, 2017
Red Zone
Defined Contribution Plan Disclosure [Line Items]
Percentage of funds required in the critical status			65.00%
Yellow Zone
Defined Contribution Plan Disclosure [Line Items]
Percentage of funds required in the critical status			80.00%
Green Zone
Defined Contribution Plan Disclosure [Line Items]
Percentage of funds required in the critical status			80.00%