Benefit Plans - Defined Benefit Plans - Estimated Net Actuarial Loss and Prior Service Cost (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Supplemental Retirement Plan
Estimated net actuarial loss and prior service cost that will be amortized from accumulated other comprehensive loss into net periodic cost over next fiscal year
Estimated net actuarial loss and prior service cost that will be amortized from accumulated other comprehensive loss into net periodic cost over next fiscal year	$ 183,000	$ 292,000
Split-Dollar Life Insurance Benefit Plan
Estimated net actuarial loss and prior service cost that will be amortized from accumulated other comprehensive loss into net periodic cost over next fiscal year
Estimated net actuarial loss and prior service cost that will be amortized from accumulated other comprehensive loss into net periodic cost over next fiscal year	$ 90,000	$ 90,000