XML 72 R56.htm IDEA: XBRL DOCUMENT v3.5.0.2
Derivatives (Effects Of Derivatives On Measures Of Financial Performance) (Details) - USD ($)
$ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2016
Sep. 30, 2015
Sep. 30, 2016
Sep. 30, 2015
Designated as Hedging Instrument [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) Recognized in Other Comprehensive Income(Effective Portion) $ (71) $ 1,075 $ (136) $ 6,126
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion) 76 3,599 397 6,807
Designated as Hedging Instrument [Member] | Coal sales [Member] | Coal Contract [Member] | Sales Revenue, Net [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) Recognized in Other Comprehensive Income(Effective Portion) (612) 3,636 (672) 12,738
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion) 108 6,683 1,634 12,555
Designated as Hedging Instrument [Member] | Coal purchases [Member] | Coal Contract [Member] | Cost of Sales [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Gain (Loss) Recognized in Other Comprehensive Income(Effective Portion) 541 (2,561) 536 (6,612)
Gains (Losses) Reclassified from Other Comprehensive Income into Income (Effective Portion) (32) (3,084) (1,237) (5,748)
Not Designated as Hedging Instrument [Member] | Coal Contract [Member] | Change in Fair Value of Coal Derivatives and Coal Trading Activity, Net [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Unrealized Gain (Loss) on Derivatives (566) (809) (1,662) (2,095)
Not Designated as Hedging Instrument [Member] | Coal Contract [Member] | Other Operating Income (Expense) [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Realized Gain (Loss) on Derivatives (133) 511 (476) 2,428
Not Designated as Hedging Instrument [Member] | Natural Gas [Member] | Change in Fair Value of Coal Derivatives and Coal Trading Activity, Net [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Unrealized Gain (Loss) on Derivatives (79) (16) (463) (78)
Not Designated as Hedging Instrument [Member] | Heating Oil-Diesel Purchases [Member] | Other Operating Income (Expense) [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Heating oil realized and unrealized gains and losses (770) (5,525) 826 (7,262)
Not Designated as Hedging Instrument [Member] | Foreign Currency [Member] | Other Operating Income (Expense) [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Heating oil realized and unrealized gains and losses $ (314) $ (602) $ (451) $ (602)