Income Taxes Income Taxes (Reconciliation Statutory Income Tax Rates) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%	21.00%	21.00%
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Percent	(1.90%)	(1.60%)	(2.20%)	(2.00%)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	1.90%	1.90%	1.60%	1.80%
Effective Income Tax Rate Reconciliation, Low-Income Housing and Rehabilitation, Percent	(0.10%)	(0.50%)	(0.60%)	(0.60%)
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent	0.30%	(2.40%)	0.30%	(2.00%)
Effective Income Tax Rate Reconciliation, Percent	21.20%	18.40%	20.10%	18.20%