Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Consolidated Statements of Comprehensive Income
Net Income	$ 40,604	$ 45,483	$ 34,775	$ 56,645
Other comprehensive income, net:
Net change related to employee benefit plans, net of tax of $899 for three months ended 2013 and $3,034 and $1,217 for nine months ended 2013 and 2012 respectively	1,381	1,863	3,347	4,120
Net change in derivative instruments, net of tax of $2,610 for three months ended 2013 and $1,942 for nine months ended 2013	(4,465)		2,991
Total other comprehensive income, net	(3,084)	1,863	6,338	4,120
Total Comprehensive Income, net	$ 37,520	$ 47,346	$ 41,113	$ 60,765