Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Statement of Comprehensive Income [Abstract]
Tax expense on current period cash flow hedging activity	$ 477	$ 2,471	$ 266
Tax expense (benefit) on reclassification of hedging activities into earnings	(95)	2,630	(2,668)
Tax expense (benefit) on current period pension and postretirement plan adjustment	5,531	(1,553)	(7,391)
Tax expense on current curtailment gain	718
Tax expense (benefit) on reclassification of pension and postretirement into earnings	$ (740)	$ (2,056)	$ (1,900)