Pensions and Other Postretirement Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 825	$ 842
Interest cost	2,359	2,000
Expected return on assets	(2,371)	(2,034)
Amortization of prior service cost/(credit)	13	9
Amortization of transition obligation		17
Amortization of net actuarial loss	601	785
Curtailment	(493)
Net periodic benefit cost	934	1,619
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	79	285
Interest cost	686	802
Expected return on assets
Amortization of prior service cost/(credit)	(1,122)	(917)
Amortization of transition obligation
Amortization of net actuarial loss	727	879
Curtailment
Net periodic benefit cost	$ 370	$ 1,049