Employee Benefit Plans - Schedule of beginning and ending balances of accumulated postretirement benefit obligations (Details) - Other Postretirement Benefit Plans, Defined Benefit - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Accumulated postretirement benefit obligations at the beginning of the year	$ 2,529,000	$ 2,126,000
Service Cost	46,000	38,000
Interest Cost	65,000	70,000
Actuarial loss	3,308,000	357,000
Benefits paid	(83,000)	(62,000)
Accumulated postretirement benefit obligations at the end of the year	$ 5,865,000	$ 2,529,000