Retirement Benefits (Fair Value of Pension Plan Assets) (Details) - Pension Plan [Member] - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
United States [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	$ 223,227	$ 204,425	$ 239,260
United States [Member] | Investments Measured At Net Asset Value [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	13,673	12,774
United States [Member] | Guaranteed Deposits [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	1,863	1,723
United States [Member] | Fixed Income Mutual Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	73,563	74,310
United States [Member] | Commingled Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	678	728
United States [Member] | Common Stock [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	4,198	4,439
United States [Member] | Equities: Mutual Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	128,546	109,756
United States [Member] | Equities: Commingled Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	706	695
United States [Member] | Total Assets In The Fair Value Hierarchy [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	209,554	191,651
Non-U.S. Pension Plans [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	33,898	32,979	$ 36,314
Non-U.S. Pension Plans [Member] | Cash And Cash Equivalents [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	10	89
Non-U.S. Pension Plans [Member] | Guaranteed Deposits [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	30,903	28,094
Non-U.S. Pension Plans [Member] | Fixed Income Mutual Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	2,352	1,070
Non-U.S. Pension Plans [Member] | Equities: Mutual Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	544	451
Non-U.S. Pension Plans [Member] | Fixed Income: Other [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	89	3,194
Non-U.S. Pension Plans [Member] | Other Assets [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets		81
Level 1 [Member] | United States [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	206,307	188,505
Level 1 [Member] | United States [Member] | Fixed Income Mutual Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	73,563	74,310
Level 1 [Member] | United States [Member] | Common Stock [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	4,198	4,439
Level 1 [Member] | United States [Member] | Equities: Mutual Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	128,546	109,756
Level 1 [Member] | United States [Member] | Total Assets In The Fair Value Hierarchy [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	206,307	188,505
Level 1 [Member] | Non-U.S. Pension Plans [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	2,995	2,702
Level 1 [Member] | Non-U.S. Pension Plans [Member] | Cash And Cash Equivalents [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	10
Level 1 [Member] | Non-U.S. Pension Plans [Member] | Guaranteed Deposits [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets		32
Level 1 [Member] | Non-U.S. Pension Plans [Member] | Fixed Income Mutual Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	2,352	1,070
Level 1 [Member] | Non-U.S. Pension Plans [Member] | Equities: Mutual Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	544	451
Level 1 [Member] | Non-U.S. Pension Plans [Member] | Fixed Income: Other [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	89	1,068
Level 1 [Member] | Non-U.S. Pension Plans [Member] | Other Assets [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets		81
Level 2 [Member] | United States [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	3,003	2,920
Level 2 [Member] | United States [Member] | Guaranteed Deposits [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	1,863	1,723
Level 2 [Member] | United States [Member] | Commingled Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	434	502
Level 2 [Member] | United States [Member] | Equities: Commingled Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	706	695
Level 2 [Member] | United States [Member] | Total Assets In The Fair Value Hierarchy [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	3,003	2,920
Level 2 [Member] | Non-U.S. Pension Plans [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	748	2,959
Level 2 [Member] | Non-U.S. Pension Plans [Member] | Cash And Cash Equivalents [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets		89
Level 2 [Member] | Non-U.S. Pension Plans [Member] | Guaranteed Deposits [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	748	744
Level 2 [Member] | Non-U.S. Pension Plans [Member] | Fixed Income: Other [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets		2,126
Level 3 [Member] | United States [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	244	226
Level 3 [Member] | United States [Member] | Commingled Funds [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	244	226
Level 3 [Member] | United States [Member] | Total Assets In The Fair Value Hierarchy [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Fair value of plan assets	244	226
Level 3 [Member] | Non-U.S. Pension Plans [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	30,155	27,318
Level 3 [Member] | Non-U.S. Pension Plans [Member] | Guaranteed Deposits [Member]
Pension Postretirement And Other Retirement Plans [Line Items]
Total fair value of plan assets	$ 30,155	$ 27,318