Consolidated Condensed Statements of Comprehensive Income (Parenthetical) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Amortization of net obligation at transition, tax	$ 26	$ 25	$ 77	$ 75
Amortization of prior service cost, tax	28	30	82	89
Amortization of net loss, including settlement charges, tax	729	413	2,383	1,238
Current period change in fair value of pension, tax	2,238	(4,073)	2,238	(4,073)
Commodity contracts
Current period change in fair value of interest rate swap, tax	42	(30,622)	(6,669)	30,621
Reclassification adjustment for derivative instruments, tax	(3,205)	(4,924)	(11,486)	(14,303)
Interest rate swap
Current period change in fair value of interest rate swap, tax	(188)	(375)	(23)	(1,205)
Reclassification adjustment for derivative instruments, tax	$ 156	$ 142	$ 449	$ 422