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Note 15 - Employee Benefit Plans (Details Textual) $ in Thousands | 12 Months Ended
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Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($)
Defined Contribution Plan, Employer Discretionary Contribution Amount | $ 1,800 | $ 1,800 | $ 1,300
Entity Number of Employees | 1,684 |  |
Multiemployer Plan, Period Contributions | $ 12,638 | 14,534 | 10,808
Individually Insignificant Multiemployer Pension Costs [Member] |  |  |
Multiemployer Plan, Period Contributions | $ 1,200 | $ 1,500 | $ 900
Red Zone [Member] |  |  |
Multiemployer Plans, Collective-Bargaining Arrangement, Percentage of Contributions | 65.00% |  |
Orange Zone [Member] |  |  |
Multiemployer Plans, Collective-Bargaining Arrangement, Percentage of Contributions | 80.00% |  |
Yellow Zone [Member] |  |  |
Multiemployer Plans, Collective-Bargaining Arrangement, Percentage of Contributions | 80.00% |  |
Yellow Zone [Member] | Minimum [Member] |  |  |
Multiemployer Plans, Collective-Bargaining Arrangement, Percentage of Contributions | 80.00% |  |
Field Personnel [Member] |  |  |
Entity Number of Employees | 1,364 |  |
Union Members [Member] | Nevada, Arizona, California, and Hawaii [Member] |  |  |
Entity Number of Employees | 366 |  |
Number of Employees, Percent | 22.00% |  |

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- Definition 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. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450702-114947 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 9 -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450691-114947 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 80 -Section 50 -Paragraph 5 -Subparagraph (e)(1) -URI http://asc.fasb.org/extlink&oid=65877416&loc=SL14450657-114947 + Details
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