Retirement Benefits (Schedule of Estimated Remaining Cash Contributions) (Details) $ in Thousands	Dec. 31, 2018 USD ($)
Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated future employer contributions in the currect fiscal year	$ 3,242
UNITED KINGDOM | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated future employer contributions in the currect fiscal year	518
Germany [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Estimated future employer contributions in the currect fiscal year	$ 748