Retirement Benefit Plans (Schedule of Defined Benefit Plans Disclosures) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Change in fair value of plan assets
Fair value of plan assets at beginning of year	$ 18,106
Fair value of plan assets at end of year	20,605	$ 18,106
Pension Plan
Change in projected benefit obligation
Benefit obligation at beginning of year	20,050	21,552
Service cost	3	4
Interest cost	819	757
Liability actuarial (gain) loss	2,604	(1,270)
Benefits paid	(1,027)	(993)
Benefit obligation at end of year	22,449	20,050
Change in fair value of plan assets
Fair value of plan assets at beginning of year	18,106	20,327
Return on plan assets	3,526	(1,228)
Employer contributions	0	0
Benefits paid	(1,027)	(993)
Fair value of plan assets at end of year	20,605	18,106
Funded status	(1,844)	(1,944)
Supplemental Employee Retirement Plan
Change in projected benefit obligation
Benefit obligation at beginning of year	7,446	5,945
Service cost	240	249
Interest cost	298	248
Liability actuarial (gain) loss	1,193	(328)
Benefits paid	(155)	(98)
Plan amendments	0	1,430
Benefit obligation at end of year	$ 9,022	$ 7,446