Employee Benefits Plans (Details 10) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Amortization of:
Postretirement benefit (income) expense	$ 138,656	$ 48,118	$ 49,413
Other Postretirement Benefits [Member]
Other Postretirement benefit expense
Service cost	446	981	1,095
Interest cost	1,421	1,580	1,980
Amortization of:
Net actuarial loss (gain)	(725)	(14)	(20)
Prior service credit	(2,459)	(231)	(231)
Postretirement benefit (income) expense	(1,317)	2,316	2,824
Other Postretirement benefit expense U.S. [Member]
Amortization of:
Postretirement benefit (income) expense	(1,839)	1,625	2,142
Other Postretirement benefit expense Foreign [Member]
Amortization of:
Postretirement benefit (income) expense	$ 522	$ 691	$ 682