Income Taxes Income Taxes (Reconciliation Statutory Income Tax Rates) (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
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	(1.60%)	(3.10%)	(2.00%)	(3.00%)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	1.90%	2.10%	1.80%	2.20%
Effective Income Tax Rate Reconciliation, Low-Income Housing and Rehabilitation, Percent	(0.40%)	(0.90%)	(0.60%)	(1.10%)
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent	(2.40%)	0.40%	(2.00%)	1.00%
Effective Income Tax Rate Reconciliation, Percent	18.50%	19.50%	18.20%	20.10%