Retirement Benefit Plans (Fair Value Hierarchy) (Details) - Defined Benefit Pension Plans - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	$ 62,030	$ 64,893
Level 1 | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	28,428	33,799
Level 1 | Non-U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	12,197	8,003
Level 1 | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	20,930	22,787
Level 1 | Money market
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	475	304
Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	4,712	4,383
Level 2 | U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	777	670
Level 2 | Non-U.S. equity securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	2,275	1,939
Level 2 | Fixed income securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	1,660	1,774
Level 2 | Money market
Defined Benefit Plan Disclosure [Line Items]
Fair value of each major category of U.S. plan assets	$ 0	$ 0