Employee Benefit Plans (Obligation and Funded Status of Pension and Postretirement Plans) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Change in benefit obligation
Benefit obligation at beginning of year	$ 3,088,000	$ 4,362,000
Service cost	0	0	$ 0
Interest cost	48,000	116,000	130,000
Actuarial (gains) losses	68,000	44,000
Participant contributions	0	0
Benefits paid	(1,320,000)	(1,434,000)
Benefit obligation at end of year	1,884,000	3,088,000	4,362,000
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Company contributions	1,320,000	1,434,000
Participant contributions	0	0
Benefits paid	(1,320,000)	(1,434,000)
Fair value of plan assets at end of year	0	0	0
Under funded status of plans at end of year	(1,884,000)	(3,088,000)
Postretirement Benefits
Change in benefit obligation
Benefit obligation at beginning of year	24,872,000	20,638,000
Service cost	221,000	365,000	319,000
Interest cost	719,000	854,000	752,000
Actuarial (gains) losses	452,000	4,687,000
Participant contributions	298,000	297,000
Benefits paid	(1,238,000)	(1,969,000)
Benefit obligation at end of year	25,324,000	24,872,000	20,638,000
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Company contributions	940,000	1,672,000
Participant contributions	298,000	297,000
Benefits paid	(1,238,000)	(1,969,000)
Fair value of plan assets at end of year	0	0	$ 0
Under funded status of plans at end of year	$ (25,324,000)	$ (24,872,000)