Retirement Benefits (Net Periodic Benefit Cost For U.S. Employees) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,040	$ 2,064	$ 8,092	$ 6,616
Interest cost	2,562	2,928	7,608	8,788
Expected return on plan assets	(5,197)	(4,492)	(15,591)	(14,523)
Amortization of net (income) loss	2,462	1,909	6,137	5,111
FAS 88 settlement charge	871	102	871	309
Net periodic benefit cost	2,738	2,511	7,117	6,301
Post-Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	311	245	763	818
Interest cost	215	245	644	835
Amortization of prior service cost	(177)	(144)	(401)	(433)
Amortization of net (income) loss		(39)		(39)
Net periodic benefit cost	$ 349	$ 307	$ 1,006	$ 1,181