Employee Benefit Plans (Components of Net Period Benefit Plans) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Components of the net periodic benefit cost
Service cost	$ 0	$ 0	$ 0
Interest cost	48	116	130
Expected return on plan assets	0	0	0
Recognized net actuarial loss	248	232	243
Net periodic benefit cost	296	348	373
Postretirement Benefits
Components of the net periodic benefit cost
Service cost	221	365	319
Interest cost	719	854	752
Expected return on plan assets	(911)	(911)	(910)
Recognized net actuarial loss	79	0	0
Net periodic benefit cost	$ 108	$ 308	$ 161