Derivatives Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2015

Derivative [Line Items]

Schedule of offsetting and balance sheet presentation

	March 31, 2015
	Gross Amounts of Recognized				Gross Amounts Offset in the Consolidated Balance Sheet				Net Amounts Presented in the Consolidated Balance Sheet
	Assets		Liabilities		Assets		Liabilities		Assets		Liabilities
International coal forward contracts	$	19,470	$	(364)	$	(364)	$	364	$	19,106	$	—
WTI derivative financial instruments		—		(8,360)		(4,232)		4,232		(4,232)		(4,128)
Total	$	19,470	$	(8,724)	$	(4,596)	$	4,596	$	14,875	$	(4,128)

	December 31, 2014
	Gross Amounts of Recognized				Gross Amounts Offset in the Consolidated Balance Sheet				Net Amounts Presented in the Consolidated Balance Sheet
	Assets		Liabilities		Assets		Liabilities		Assets		Liabilities
International coal forward contracts	$	20,861	$	(129)	$	(129)	$	129	$	20,732	$	—
WTI derivative financial instruments		—		(7,228)		(3,620)		3,620		(3,620)		(3,608)
Total	$	20,861	$	(7,357)	$	(3,749)	$	3,749	$	17,111	$	(3,608)

Schedule of derivative mark-to-market (gains) and losses recognized in the consolidated statement of operations and comprehensive income

	Three Months Ended
	March 31,
	2015		2014
International coal forward contracts	$	(1,968)	$	(10,592)
Domestic coal futures contracts		3,898		(1,833)
WTI derivative financial instruments		2,855		(309)
Total	$	4,785	$	(12,734)

Coal Contracts

Derivative [Line Items]

Schedule of derivative financial instruments

	2015		2016		Total
International Coal Forward Contracts
Notional amount (tons)		344		132		476
Net asset position	$	12,408	$	6,698	$	19,106
Domestic Coal Futures Contracts
Notional amount (tons)		1,440		120		1,560

WTI derivative financial instruments

Derivative [Line Items]

Schedule of derivative financial instruments

	Floor			Ceiling			Swaps
Settlement Period	Notional Amount	Weighted-Average per Barrel		Notional Amount	Weighted-Average per Barrel		Notional Amount	Weighted-Average per Barrel
	(barrels in thousands)			(barrels in thousands)			(barrels in thousands)
2015 collar positions (1)	264	$	74.14	264	$	80.00	—	$	—
2015 swap positions (2)	—		—	—		—	255		52.18
2016 collar positions (3)	342		53.94	342		72.88	—		—
2016 swap positions (3)	—		—	—		—	342		63.39
Total	606	$	64.80	606	$	76.46	597	$	58.59

• Represents 75% of expected diesel consumption for the second and third quarters of 2015.
• Represents 25% of expected diesel consumption for the second and third quarters of 2015 and 100% of expected diesel consumption for the fourth quarter of 2015.
• Represents 50% of expected diesel consumption for 2016.