Employee Benefits Plans (Details 13) (Other Postretirement Benefits [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Other Postretirement Benefits [Member]
Amounts recognized in the Consolidated Balance Sheets
Current liability	$ (2,683)	$ (2,838)
Noncurrent liability	(37,916)	(40,154)
Net amount recognized	(40,599)	(42,992)
Amounts recognized in accumulated other comprehensive loss (pre-tax)
Prior service credit	(1,307)	(1,538)
Net actuarial loss	(859)	867
Net amount recognized	$ (2,166)	$ (671)