CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
CONDENSED CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME
Net income	$ 42,824		$ 18,318
Other comprehensive income / (loss), net of taxes:
Reclassification adjustment for settled hedge contracts	(9,325)	[1]	(34,070)	[1]
Changes in fair value of hedge contracts	(36,975)	[2]	43,205	[2]
Pension and postretirement benefits:
Amortization of prior service cost			68	[3]
Amortization of net loss	125	[4]	4,175	[4]
Total other comprehensive income / (loss)	(46,175)		13,378
Comprehensive income / (loss)	$ (3,351)		$ 31,696

[1] Net of income taxes of $6,045 and $21,600 for the three months ended March 31, 2013 and 2012, respectively.

[2] Net of income taxes of $23,917 and $(27,523) for the three months ended March 31, 2013 and 2012, respectively.

[3] Net of income taxes of $0 and $(43) for the three months ended March 31, 2013 and 2012, respectively.

[4] Net of income taxes of $(80) and $(2,647) for the three months ended March 31, 2013 and 2012, respectively.