Pensions (Details 5) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Components of net periodic pension costs of the plans
Settlement		$ 1,369
U.S. Plans
Components of net periodic pension costs of the plans
Service cost	1,165	1,059	1,022
Interest cost	4,423	4,796	4,942
Expected return on assets	(6,660)	(6,166)	(6,669)
Prior service cost	74	74	75
Net amortization	3,519	3,430	1,728
Settlement		1,369
Net periodic pension cost	2,521	4,562	1,098
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss)
Current year actuarial (gain) loss	(21,997)	7,672
Amortization of actuarial loss	(3,519)	(3,430)
Amortization of prior service cost	(74)	(74)
Settlement		(1,369)
Total recognized in other comprehensive income (loss)	(25,590)	2,799
Total recognized in net periodic pension cost and other comprehensive income (loss)	(23,069)	7,361
Estimated amounts that will be amortized from accumulated other comprehensive income into net periodic pension cost in 2014
Prior service cost	74
Net actuarial loss	950
Estimated amounts that will be amortized from accumulated other comprehensive income into net periodic pension cost in 2014	1,024
Assumptions used in the measurement of net periodic pension cost
Discount rate (as a percent)	3.92%	4.67%	5.26%
Expected annual return on plan assets (as a percent)	7.75%	7.75%	8.00%
Rate of increase in compensation levels (as a percent)	4.00%	4.00%	4.00%
European Plans
Components of net periodic pension costs of the plans
Service cost	314	148	155
Interest cost	1,511	1,640	1,947
Expected return on assets	(1,263)	(1,232)	(1,442)
Net amortization	203	15	68
Settlement	279
Special termination benefits			200
Net periodic pension cost	1,044	571	928
Other Changes in Plan Assets and Benefit Obligations Recognized in Other Comprehensive Income (Loss)
Current year actuarial (gain) loss	1,046	4,382
Amortization of actuarial loss	(203)	(15)
Foreign currency exchange	292	296
Settlement	(279)
Total recognized in other comprehensive income (loss)	856	4,663
Total recognized in net periodic pension cost and other comprehensive income (loss)	1,900	5,234
Estimated amounts that will be amortized from accumulated other comprehensive income into net periodic pension cost in 2014
Net actuarial loss	$ 245
Assumptions used in the measurement of net periodic pension cost
Discount rate (as a percent)	3.99%	5.00%	5.35%
Expected annual return on plan assets (as a percent)	4.91%	4.92%	6.03%
Rate of increase in compensation levels (as a percent)	3.50%	3.50%	3.50%