Note 3 - Properties, Plants, Equipment and Mineral Interests, and Lease Commitments (Details) - Future Obligations Under Non-cancelable Operating Leases (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Future Obligations Under Non-cancelable Operating Leases [Abstract]
2015	$ 3,456
2016	3,364
2017	2,962
2018	966
2019	968
Thereafter	2,081
Total	$ 13,797

Note 3 - Properties, Plants, Equipment and Mineral Interests, and Lease Commitments (Details) - Future Obligations Under Non-cancelable Operating Leases (USD $)
In Thousands, unless otherwise specified

Dec. 31, 2014

Future Obligations Under Non-cancelable Operating Leases [Abstract]

$ 3,456us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent

2016

3,364us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears

2017

2,962us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears

2018

966us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears

2019

968us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears

Thereafter

2,081us-gaap_OperatingLeasesFutureMinimumPaymentsDueThereafter

Total

$ 13,797us-gaap_OperatingLeasesFutureMinimumPaymentsDue

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Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 20

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

-SubTopic 10

-Section 55

-Paragraph 40

-Subparagraph (Note 3)

-URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697

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- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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- Definition

Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

+ References

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