Retirement Benefit Plans (Changes in Other Comprehensive Income) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	$ (12,052)	$ 5,262	$ (2,202)
Amounts reclassified from AOCL	(4,102)	(3,976)	(5,706)
Total (gain) loss recognized in OCI	(16,154)	1,286	(7,908)
Pension Plan [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	(12,008)	5,375	(2,263)
Amounts reclassified from AOCL	(4,102)	(4,027)	(5,705)
Total (gain) loss recognized in OCI	(16,110)	1,348	(7,968)
SERP [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	(77)	194	164
Amounts reclassified from AOCL	(38)	(23)	(14)
Total (gain) loss recognized in OCI	(115)	171	150
Other Benefits [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Net (gain) loss	33	(307)	(103)
Amounts reclassified from AOCL	38	74	13
Total (gain) loss recognized in OCI	$ 71	$ (233)	$ (90)