Employee Benefit Plans (Obligation and Funded Status of Pension and Postretirement Plans) (Details) - Postretirement health care benefit plan - USD ($)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Change in benefit obligation
Benefit obligation at beginning of year	$ 17,433,000	$ 23,942,000
Service cost	151,000	248,000	$ 302,000
Interest cost	830,000	586,000	546,000
Actuarial (gains) losses	(66,000)	(6,180,000)
Participant contributions	257,000	314,000
Benefits paid	(1,339,000)	(1,477,000)
Benefit obligation at end of year	17,266,000	17,433,000	23,942,000
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Company contributions	1,082,000	1,163,000
Participant contributions	257,000	314,000
Benefits paid	(1,339,000)	(1,477,000)
Fair value of plan assets at end of year	0	0	$ 0
Under funded status of plans at end of year	$ (17,266,000)	$ (17,433,000)