Income Taxes Income Taxes (Reconciliation Statutory Income Tax Rates) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 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	(2.40%)	(1.90%)	(2.50%)	(2.20%)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	1.60%	1.60%	1.80%	1.80%
Effective Income Tax Rate Reconciliation, Low-Income Housing and Rehabilitation, Percent	(1.10%)	(0.90%)	(0.70%)	(0.70%)
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent	(1.20%)	(1.80%)	(0.60%)	(1.70%)
Effective Income Tax Rate Reconciliation, Percent	17.90%	18.00%	19.00%	18.20%