Benefit Plans - Defined Benefit Plans - Components of Pension Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Supplemental Retirement Plan
Components of net periodic benefit cost:
Service cost	$ 123	$ 55	$ 246	$ 110
Interest cost	236	264	467	528
Amortization of net actuarial loss	105	46	190	92
Net periodic benefit cost	464	365	903	730
Plan assets associated with the plan	0		0
Split-Dollar Life Insurance Benefit Plan
Components of net periodic benefit cost:
Interest cost	62	70	124	140	$ 278
Amortization of prior transition obligation	(15)	(24)	(30)	(49)
Net periodic benefit cost	$ 47	$ 46	$ 94	$ 91