Pension and Postretirement Plans (Consolidated Balance Sheet) (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Pension Plans [Member]
Noncurrent asset	$ 604,823	$ 537,262
Current liability	0	0
Noncurrent liability	0	0
Recognized asset (liability)	604,823	537,262
Supplemental Executive Retirement Plan (SERP) [Member]
Noncurrent asset	0	0
Current liability	(4,368)	(4,002)
Noncurrent liability	(99,694)	(88,861)
Recognized asset (liability)	(104,062)	(92,863)
Other Postretirement Plans [Member]
Current liability	(3,919)	(4,548)
Noncurrent liability	(59,949)	(67,864)
Recognized asset (liability)	$ (63,868)	$ (72,412)