Retirement Benefits (Net Periodic Benefit Cost For U.S. Employees) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Defined Benefit Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 2,041	$ 2,276	$ 6,052	$ 4,552
Interest cost	2,563	2,930	5,046	5,860
Expected return on plan assets	(5,197)	(5,016)	(10,394)	(10,031)
Amortization of net (income) loss	2,462	1,601	3,675	3,203
FAS 88 settlement charge		104		208
Net periodic benefit cost	1,869	1,895	4,379	3,792
Post-Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	311	286	452	573
Interest cost	215	295	429	590
Amortization of prior service cost	(176)	(144)	(224)	(289)
Net periodic benefit cost	$ 350	$ 437	$ 657	$ 874