Consolidated Statements of Comprehensive Income (Loss) (Parenthetical) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Derivatives qualifying as hedges tax expense (benefit)	$ (838)	$ 477	$ 2,471
Reclassification adjustment from AOCI on derivatives tax expense (benefit)	(489)	(95)	2,630
Pension and other postretirement benefit plans tax expense (benefit)	(3,292)	5,531	(1,553)
Finalization of pension and non pension postretirement plan valuation tax expense	0	718	0
Amortization adjustment from AOCI pension and other post retirement plans, tax expense (benefit)	$ (313)	$ (740)	$ (2,056)