Pensions and Other Post-retirement Benefits (Details 1) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Net periodic benefit cost
Expected return on plan assets		$ 0	$ 0
Change in other comprehensive income
OCI at beginning of year		56,004
Increase (decrease) in OCI:
OCI at end of year	94,136	79,507	56,004
Pension Benefits [Member]
Net periodic benefit cost
Service cost	7,915	6,955	5,135
Interest cost	9,912	9,786	9,156
Expected return on plan assets	(11,934)	(11,050)	(10,441)
Amortization of prior service cost (benefit)	(335)	(335)	(530)
Recognized net actuarial loss	(5,605)	(3,920)	(2,834)
Net periodic benefit cost	11,163	9,276	6,154
Change in other comprehensive income
OCI at beginning of year	104,056	69,716	62,886
Increase (decrease) in OCI:
Recognized during year- prior service cost (credit)	335	335	530
Recognized during year-net actuarial (losses) gains	(5,605)	(3,920)	(2,834)
Occurring during year-prior service cost	117	430	739
Occurring during year-net actuarial losses (gains)	25,995	37,543	8,390
Other adjustments	0	0	0
Foreign currency exchange rate changes	57	(48)	5
OCI at end of year	124,955	104,056	69,716
Other Benefits [Member]
Net periodic benefit cost
Service cost	285	284	273
Interest cost	1,440	1,596	1,738
Expected return on plan assets	0
Amortization of prior service cost (benefit)	86	(36)	(36)
Recognized net actuarial loss	0	0	0
Net periodic benefit cost	1,811	1,844	1,975
Change in other comprehensive income
OCI at beginning of year	1,180	(275)	(2,085)
Increase (decrease) in OCI:
Recognized during year- prior service cost (credit)	(87)	36	36
Recognized during year-net actuarial (losses) gains	0	0	0
Occurring during year-prior service cost	0	0	0
Occurring during year-net actuarial losses (gains)	1,494	1,419	1,774
Other adjustments	0	0	0
Foreign currency exchange rate changes	0	0	0
OCI at end of year	$ 2,587	$ 1,180	$ (275)