Postretirement Benefit Plan (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2021 USD ($) age	Sep. 30, 2020 USD ($)	Sep. 30, 2021 USD ($) age	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)
Postretirement Benefit Plan
Minimum age entity to pay health and life insurance for retired executive | age	65		65
Future obligation of benefits	$ 2,556,000		$ 2,556,000		$ 2,529,000
Benefit cost	$ 48,000	$ 98,000	$ 143,000	$ 296,000