Retirement Benefit Plans (Fair Value Hierarchy) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
U.S. Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	$ 28,900	$ 25,671
U.S. Plan | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	13,255	11,251
U.S. Plan | Non-U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	5,904	4,930
U.S. Plan | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	9,596	9,350
U.S. Plan | Money market
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	145	140
Non-U.S. Plan
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	5,350	4,744
Non-U.S. Plan | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	929	735
Non-U.S. Plan | Non-U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	2,412	2,081
Non-U.S. Plan | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	2,009	1,928
Non-U.S. Plan | Money market
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	$ 0	$ 0