Employee Benefit Plan (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020
Postretirement Benefit Plan
Future obligation of benefits	$ 2,547,000		$ 2,547,000		$ 2,529,000
Benefit cost	$ 46,000	$ 99,000	$ 92,000	$ 198,000