Retirement Benefit Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items]
Service cost			$ 9	$ 9
Interest cost			966	954
Expected return on plan assets			(1,384)	(1,416)
Amortization of net loss			543	486
Net periodic benefit cost	$ 45	$ 11	134	33
Hourly Employees’ Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost			6	6
Interest cost			300	303
Expected return on plan assets			(486)	(495)
Amortization of net loss			213	186
Net periodic benefit cost			33	0
Employees’ Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Service cost			3	3
Interest cost			666	651
Expected return on plan assets			(898)	(921)
Amortization of net loss			330	300
Net periodic benefit cost			$ 101	$ 33