SERP Benefits Table (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Change in plan assets
Fair value of plan assets at beginning of year	$ 16,600
Fair value of plan assets at end of year	18,300	$ 16,600
Supplemental Executive Retirement Plans [Member]
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation at beginning of year	14,963	15,749	$ 14,177
Service cost	433	459	423
Interest cost	601	533	547
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)	(1,850)	1,344	(969)
Accumulated benefit obligation at end of year	17,361	14,963	15,749
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(486)	(434)	(367)
Change in plan assets
Employer contribution	486	434	367
Defined Benefit Plan, Plan Assets, Benefits Paid	(486)	(434)	(367)
Funded status at end of year	(17,361)	(14,963)	(15,749)
Assets for Plan Benefits, Defined Benefit Plan	0	0	0
Liabilities	(17,361)	(14,963)	(15,749)
Funded status at end of year	(17,361)	(14,963)	(15,749)
Accumulated Other Comprehensive (Income) Loss, Defined Benefit Plan, after Tax [Abstract]
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), Gain (Loss), before Tax	3,509	1,705	3,465
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, Prior Service Cost (Credit), before Tax	494	770	1,047
Defined Benefit Plan, Accumulated Other Comprehensive (Income) Loss, before Tax	4,003	2,475	4,512
Information for plans with an accumulated benefit obligation in excess of plan assets
Projected benefit obligation	17,361	14,963	15,749
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	17,361	14,963	15,749
Net periodic benefit cost
Service cost	433	459	423
Interest cost	601	533	547
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	276	276	276
Recognized net actuarial loss	46	415	334
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)	1,356	1,683	1,580
Defined Benefit Plan, Expected Amortization, Next Fiscal Year [Abstract]
Net actuarial loss	471	41	415
Net prior service cost	$ 276	$ 276	$ 276
Minimum [Member] | Supplemental Executive Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	2.00%	3.24%	2.48%
Defined Benefit Plan, Expected Amortization, Next Fiscal Year [Abstract]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	3.24%	2.48%	2.49%
Maximum [Member] | Supplemental Executive Retirement Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.04%	4.09%	3.45%
Defined Benefit Plan, Expected Amortization, Next Fiscal Year [Abstract]
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate	4.09%	3.45%	3.94%