Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Net Income (Loss)	$ (15,420)	$ 53,316
Other comprehensive income (loss):
Total cash flow hedges	0	(2,337)
Pension and postretirement plans:
Amortization of net benefit obligation at transition, net of tax of $0 and $3, respectively	0	6
Amortization of prior service cost, net of tax of $0 and $26, respectively	0	48
Amortization of net loss, including settlement charges, net of tax of $996 and $2,994, respectively	1,851	5,559
Total pension and postretirement plans	1,851	5,613
Comprehensive Income (Loss)	(13,569)	56,592
Commodity contracts
Other comprehensive income (loss):
Current period change in fair value of derivative commodity instruments, net of tax	0	2
Reclassification adjustment for derivative commodity instruments, net of tax	0	(2,513)
Interest rate swap
Other comprehensive income (loss):
Current period change in fair value of derivative commodity instruments, net of tax	0	(115)
Reclassification adjustment for derivative commodity instruments, net of tax	$ 0	$ 289