Retirement Benefit Plans (Net Periodic Benefit Expense) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 1,581	$ 1,746
Expected return on plan assets	(2,852)	(2,843)
Amortization of actuarial loss	484	363
Amortization of prior service cost	58	58
Settlements	0	76
Net periodic pension income	(729)	(600)
Other Postretirement Benefits Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost	50	50
Interest cost	98	101
Amortization of actuarial loss	96	97
Amortization of prior service cost	(64)	(17)
Net periodic pension income	$ 180	$ 231