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Note 14 - Commitments and Contingencies (Details Textual) $ in Thousands	1 Months Ended		12 Months Ended
	Jan. 31, 2015 USD ($)	Jul. 31, 2014 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2014 USD ($)
Estimated Cost of EPA Selected Remedy			$ 1,050,000
Estimated Time to Complete Selected EPA Remedy			13 years
Number Of Potentially Responsible Parties			100
Insurance Recoveries	$ 2,600
Estimated Litigation Liability, Current			$ 1,750
Letters of Credit Outstanding, Amount			2,000
Pending Litigation [Member]
Estimated Litigation Liability, Current			1,800
Portland Harbor Natural Resources Trustee Council [Member]
Loss Contingency, Accrual, Current					$ 400
Loss Contingency Accrual, Payments		$ 200
Voluntary Cleanup Program [Member] | Estimated [Member]
Accrual for Environmental Loss Contingencies			200
Voluntary Cleanup Program [Member] | Minimum [Member]
Loss Contingency, Estimate of Possible Loss			100
Voluntary Cleanup Program [Member] | Maximum [Member]
Loss Contingency, Estimate of Possible Loss			$ 1,700

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The estimated cost of the remedy selected by EPA.

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Total costs accrued as of the balance sheet date for environmental loss contingencies.

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Amount of cash outflow reducing loss contingency liability.

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