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Financial Derivative Instruments and Risk Management - Notional Amounts of the Outstanding Fuel Derivatives (Details)
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3 Months Ended |
12 Months Ended |
|
Mar. 31, 2015
gal
|
Dec. 31, 2014
gal
|
| Derivatives, Fair Value [Line Items] |
|
|
| Notional amounts |
60,000,000 |
68,000,000 |
| Designated as Hedging Instrument | Energy Related Derivative |
|
|
| Derivatives, Fair Value [Line Items] |
|
|
| Notional amounts |
30,000,000 |
52,000,000 |
| Designated as Hedging Instrument | Energy Related Derivative | Heating Oil | Collars |
|
|
| Derivatives, Fair Value [Line Items] |
|
|
| Notional amounts |
16,000,000 |
36,000,000 |
| Designated as Hedging Instrument | Energy Related Derivative | Heating Oil | Swaps |
|
|
| Derivatives, Fair Value [Line Items] |
|
|
| Notional amounts |
7,000,000 |
0 |
| Designated as Hedging Instrument | Energy Related Derivative | Brent Calls | Calls |
|
|
| Derivatives, Fair Value [Line Items] |
|
|
| Notional amounts |
0 |
16,000,000 |
| Designated as Hedging Instrument | Energy Related Derivative | Jet Fuel | Swaps |
|
|
| Derivatives, Fair Value [Line Items] |
|
|
| Notional amounts |
7,000,000 |
0 |
| Not Designated as Hedging Instrument | Energy Related Derivative |
|
|
| Derivatives, Fair Value [Line Items] |
|
|
| Notional amounts |
30,000,000 |
16,000,000 |
| Not Designated as Hedging Instrument | Energy Related Derivative | Heating Oil | Collars |
|
|
| Derivatives, Fair Value [Line Items] |
|
|
| Notional amounts |
3,000,000 |
3,000,000 |
| Not Designated as Hedging Instrument | Energy Related Derivative | Heating Oil | Swaps |
|
|
| Derivatives, Fair Value [Line Items] |
|
|
| Notional amounts |
3,000,000 |
0 |
| Not Designated as Hedging Instrument | Energy Related Derivative | Brent Calls | Calls |
|
|
| Derivatives, Fair Value [Line Items] |
|
|
| Notional amounts |
24,000,000 |
13,000,000 |
| Not Designated as Hedging Instrument | Energy Related Derivative | Jet Fuel | Swaps |
|
|
| Derivatives, Fair Value [Line Items] |
|
|
| Notional amounts |
0 |
0 |