Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Components of Net periodic pension cost for the Company's defined benefit pension plans and U.S. post-retirement medical plan
Service cost, net	$ 4,919	$ 4,189	$ 9,873	$ 8,416
Interest cost on projected benefit obligations	5,158	7,178	10,354	14,320
Expected return on plan assets	(11,734)	(11,733)	(23,427)	(23,414)
Net amortization and deferral	(1,453)	(1,225)	(2,895)	(2,459)
Recognition of actuarial losses/(gains)	4,881	1,942	9,764	3,888
Net periodic pension cost/(credit)	1,771	351	3,669	751
United States Pension Plans of US Entity, Defined Benefit [Member]
Components of Net periodic pension cost for the Company's defined benefit pension plans and U.S. post-retirement medical plan
Service cost, net	208	223	417	446
Interest cost on projected benefit obligations	1,608	1,599	3,216	3,198
Expected return on plan assets	(2,394)	(2,137)	(4,788)	(4,274)
Net amortization and deferral	0	0	0	0
Recognition of actuarial losses/(gains)	1,907	1,200	3,814	2,400
Net periodic pension cost/(credit)	1,329	885	2,659	1,770
Foreign Pension Plans, Defined Benefit [Member]
Components of Net periodic pension cost for the Company's defined benefit pension plans and U.S. post-retirement medical plan
Service cost, net	4,711	3,923	9,456	7,885
Interest cost on projected benefit obligations	3,515	5,519	7,069	11,002
Expected return on plan assets	(9,340)	(9,596)	(18,639)	(19,140)
Net amortization and deferral	(984)	(1,030)	(1,957)	(2,070)
Recognition of actuarial losses/(gains)	3,817	1,100	7,635	2,206
Net periodic pension cost/(credit)	1,719	(84)	3,564	(117)
Net Periodic Benefit Cost (Textuals) [Abstract]
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year			19,600
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Components of Net periodic pension cost for the Company's defined benefit pension plans and U.S. post-retirement medical plan
Service cost, net	0	43	0	85
Interest cost on projected benefit obligations	35	60	69	120
Expected return on plan assets	0	0	0	0
Net amortization and deferral	(469)	(195)	(938)	(389)
Recognition of actuarial losses/(gains)	(843)	(358)	(1,685)	(718)
Net periodic pension cost/(credit)	$ (1,277)	$ (450)	(2,554)	$ (902)
Net Periodic Benefit Cost (Textuals) [Abstract]
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year			$ 700