Pensions and Other Postretirement Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,683	$ 1,684
Interest cost	4,815	4,000
Expected return on assets	(4,846)	(4,068)
Amortization of prior service cost/(credit)	27	17
Amortization of transition obligation		34
Amortization of net actuarial loss	1,229	1,571
Curtailment	(710)
Net periodic benefit cost	2,198	3,238
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	157	571
Interest cost	1,371	1,604
Expected return on assets
Amortization of prior service cost/(credit)	(2,244)	(1,834)
Amortization of transition obligation
Amortization of net actuarial loss	1,454	1,757
Curtailment
Net periodic benefit cost	$ 738	$ 2,098