Pensions and Other Post-retirement Benefits (Details) (Pension Plans, Defined Benefit [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 0	$ 55	$ 0	$ 111
Interest cost	5,349	5,616	10,698	11,232
Expected return on plan assets	(6,727)	(6,924)	(13,494)	(13,849)
Amortization of prior service cost	10	16	20	31
Amortization of actuarial loss	2,020	2,362	4,040	4,725
Net periodic pension cost	$ 652	$ 1,125	$ 1,264	$ 2,250