Pension and Postretirement Benefits (Details) (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 [Member]
Net periodic benefit cost of pension and post retirement benefit plans
Service cost	$ 27	$ 37	$ 54	$ 74
Interest cost	290	300	587	600
Expected return on plan assets	(70)	(141)	(221)	(282)
Recognized net actuarial loss	128	171	258	341
Net periodic benefit cost	375	367	678	733
Postretirement Benefit Plans [Member]
Net periodic benefit cost of pension and post retirement benefit plans
Service cost	42	37	79	74
Interest cost	227	232	424	464
Expected return on plan assets	(19)	(33)	(41)	(66)
Amortization of prior service credit	(279)	(319)	(557)	(638)
Recognized net actuarial loss	155	160	309	320
Net periodic benefit cost	126	77	214	154
Foreign Pension Plans [Member]
Net periodic benefit cost of pension and post retirement benefit plans
Service cost	122	94	244	185
Interest cost	183	186	371	369
Expected return on plan assets	(155)	(171)	(313)	(337)
Net periodic benefit cost	$ 150	$ 109	$ 302	$ 217