Benefit Plans - Defined Benefit Plans - Components of Pension Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Supplemental Retirement Plan
Components of net periodic benefit cost:
Service cost	$ 249	$ 325
Interest cost	947	1,034
Amortization of net actuarial loss	292	276
Net periodic benefit cost	1,488	1,635
Split-Dollar Life Insurance Benefit Plan
Components of net periodic benefit cost:
Interest cost	227	243
Amortization of prior transition obligation	(65)	(71)
Net periodic benefit cost	$ 162	$ 172