Employee Benefits Plans (Details 10) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Other Postretirement Benefits [Member]
Other Postretirement benefit expense
Service cost	$ 1,095	$ 1,294	$ 1,374
Interest Cost	1,980	2,503	2,722
Amortization of:
Net actuarial loss	(20)	231	352
Prior service credit	(231)	(231)	(231)
Net pension expense	2,824	3,797	4,217
Other Postretirement benefit expense U.S. [Member]
Amortization of:
Net pension expense	2,142	3,155	3,134
Other Postretirement benefit expense Foreign [Member]
Amortization of:
Net pension expense	$ 682	$ 642	$ 1,083