Employee Benefits Plans (Details 12) (Other Postretirement Benefits [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Postretirement Benefits [Member]
Benefit Obligations associated with postretirement benefit plans
Benefit obligations at January 1	$ 42,992	$ 47,169
Service cost	1,095	1,294	1,374
Interest Cost	1,980	2,503	2,722
Actuarial gain	(1,746)	(5,754)
Benefits paid	(3,947)	(2,023)
Foreign currency exchange rate changes	225	(197)
Benefit obligations at December 31	$ 40,599	$ 42,992	$ 47,169