Income Taxes - Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amount
Amount of Statutory Rate	$ 8,048	$ 6,750	$ 9,463
State Income Taxes (Net of Federal Income Tax Benefit)	2,711	2,755	1,757
Interest on Investment Securities and Loans Exempt From Federal Income Tax	(734)	(719)	(1,170)
Tax Credits	(2,781)	(3,207)	(1,621)
Deferred Tax Asset Revaluation			2,005
Other Differences	(321)	(355)	(285)
Totals	$ 6,923	$ 5,224	$ 10,149
Percent
Statutory Rate (as a percent)	21.00%	21.00%	35.00%
State Income Taxes (Net of Federal Income Tax Benefit) (as a percent)	7.10%	8.60%	6.50%
Interest on Investment Securities and Loans Exempt From Federal Income Tax (as a percent)	(1.90%)	(2.20%)	(4.30%)
Tax Credits (as a percent)	(7.30%)	(10.00%)	(6.00%)
Deferred Tax Asset Revaluation (as a percent)			7.40%
Other Differences (as a percent)	(0.80%)	(1.10%)	(1.10%)
Total (as a percent)	18.10%	16.30%	37.50%