Percentage of estimated annual fuel requirements hedged for the remainder of the period.

No definition available.

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- Definition

Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
-Sentence Column B

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- Definition

Fair value of all asset derivatives designated as cash flow hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624163-113959

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- Definition

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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- Definition

Fixed interest rate related to the interest rate derivative.

+ References

No definition available.

+ Details

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- Definition

The estimated value of gains (losses), net anticipated to be transferred in the future from accumulated other comprehensive income into earnings.

+ References

No definition available.

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- Definition

The effective portion of net gain (loss) reclassified from accumulated other comprehensive income into income on derivative instruments designated and qualifying as hedging instruments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4C
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624171-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4D
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624177-113959

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- Definition

Aggregate fair value of all derivative liabilities designated as hedging instruments. Includes instruments designated as cash flow hedges, fair value hedges, and hedges of net investments in foreign operations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 10
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=73719730&loc=d3e13433-108611

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- Definition

Nominal volume used to calculate payments on a derivative instrument.

+ References

No definition available.

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Balance Type:	na
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- Definition

Specified interest rate, security price, commodity price, foreign exchange rate, index of prices or rates for a derivative contract measured in volume but not the derivative contract itself.

+ References

No definition available.

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Note 6 - Derivative Instruments (Details Textual) bbl in Millions, $ in Millions	3 Months Ended	9 Months Ended	12 Months Ended
	Sep. 30, 2016 USD ($)	Sep. 30, 2016 USD ($) $ / item bbl	Dec. 31, 2015 $ / item	Aug. 31, 2015 USD ($)
Interest Rate Swap [Member] \| Other Liabilities [Member]
Derivative Instruments in Hedges, Liabilities, at Fair Value	$ 3.0	$ 3.0
Interest Rate Swap [Member] \| Interest Expense [Member]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0.1	0.1
Interest Rate Swap [Member]
Derivative, Notional Amount				$ 28.0
Derivative, Fixed Interest Rate				4.20%
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	0.4	$ 0.4
Fuel Hedge Contracts for 2016 Fuel Requirements [Member]
Derivative, Nonmonetary Notional Amount, Volume \| bbl		3.0
Percent of Projected Fuel Requirements		26.50%
Fuel Hedge Contracts for 2017 Fuel Requirements [Member]
Derivative, Nonmonetary Notional Amount, Volume \| bbl		12.1
Percent of Projected Fuel Requirements		26.50%
Fuel Hedge Contracts for 2018 Requirements [Member]
Derivative, Nonmonetary Notional Amount, Volume \| bbl		7.6
Percent of Projected Fuel Requirements		16.60%
Expired or Sold Contracts [Member]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	4.0	$ 13.1
Other Liabilities [Member]
Cash Flow Hedge Derivative Instrument Assets at Fair Value	$ 9.9	$ 9.9
Minimum [Member]
Underlying, Derivative Volume \| $ / item		1.52	1.77
Maximum [Member]
Underlying, Derivative Volume \| $ / item		1.2	1.32
Derivative Instruments, Gain (Loss) Reclassification from Accumulated OCI to Income, Estimated Net Amount to be Transferred		$ 0.3
Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months		$ 4.5