Statements of Consolidated Comprehensive Income (Loss) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net Income	$ 104,546	$ 88,443	$ 3,985
Foreign currency translation adjustment	481	(1,331)	(913)
Unrealized gain (loss) on available-for-sale security, net of deferred tax	226	(6)	29
Actuarial loss, net of deferred tax	(2,977)	(163,312)	(48,685)
Net loss included in net periodic benefit expense or income net of deferred tax	12,465	6,837	5,800
Prior-service credit, net of deferred tax	(27,493)	0	121
Amortization of prior service credit included in net periodic benefit expense or income, net of deferred tax	(727)	(730)	(724)
Employee benefit plans	(18,732)	(157,205)	(43,488)
Total Other Comprehensive Loss	(18,025)	(158,542)	(44,372)
Comprehensive Income (Loss)	$ 86,521	$ (70,099)	$ (40,387)