Summary of Significant Accounting Policies (Details 8) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Net unrealized gain (loss) on derivative instruments qualifying as hedges: [Abstract]
Net unrealized gain (loss) on derivative instruments arising during the period	$ 7,900,000	$ (3,077,000)	$ (4,094,000)
Less: Reclassification adjustment for gain (loss) on derivative instruments included in net income	0	(3,750,000)	47,590,000
Net unrealized gain (loss) on derivative instruments qualifying as hedges	7,900,000	673,000	(51,684,000)
Postretirement liability adjustment, net of tax	(22,427,000)	(5,730,000)	9,918,000
Foreign currency translation adjustment, net of tax	(1,295,000)	(5,371,000)	10,568,000
Net unrealized gains on available-for-sale investments, net of tax	82,000	0	0
Other Comprehensive Income (Loss), Net of Tax	(15,740,000)	(10,428,000)	(31,198,000)
Other Comprehensive Income (Loss), Parenthetical [Abstract]
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax	4,683,000	(1,867,000)	(2,509,000)
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Tax	0	(2,305,000)	29,170,000
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Tax	(13,573,000)	(3,609,000)	6,291,000
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Tax	44,000	0	0
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax	(832,000)	(3,486,000)	6,814,000
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net unrealized gain (loss) on derivative instruments qualifying as hedges	6,275,000	(1,625,000)	(2,298,000)
Post-retirement liability adjustment	(53,320,000)	(30,893,000)	(25,163,000)
Foreign currency translation adjustment	(38,000)	1,257,000	6,628,000
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	82,000	0	0
Total accumulated other comprehensive income (loss)	$ (47,001,000)	$ (31,261,000)	$ (20,833,000)