Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Net income	$ 689,800	$ 530,100	$ 328,000
Other comprehensive income (loss)
Change in derivative instruments designated as cash flow hedges, net of tax	700	700	(1,400)
Foreign currency translation adjustment	14,700	(8,500)	12,100
Benefit plan adjustments, net of tax	44,900	(6,800)	(21,100)
Other comprehensive income (loss)	60,300	(14,600)	(10,400)
Comprehensive income	$ 750,100	$ 515,500	$ 317,600