Income Taxes, Reconciliation of Federal Statutory Rate to Actual Effective Rate (Details)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of federal statutory rate to actual effective rate [Abstract]
Federal statutory income tax rate	21.00%	21.00%	34.00%
Increase (decrease) in tax rate due to [Abstract]
State franchise tax, net of federal benefit	8.30%	8.20%	6.90%
Reduction for tax exempt interest	(1.20%)	(0.80%)	(0.60%)
Cash surrender value of life insurance	(0.50%)	(0.50%)	(0.90%)
Tax rate change	0.00%	0.00%	9.80%
Other tax credits	(0.10%)	(0.50%)	(1.10%)
Other	0.30%	0.00%	0.60%
Effective income tax rate	27.80%	27.40%	48.70%