Income Taxes Income Taxes (Reconciliation Statutory Income Tax Rates) (Details)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	21.00%	21.00%
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Percent	(2.50%)	(2.60%)
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent	2.00%	2.20%
Effective Income Tax Rate Reconciliation, Low-Income Housing and Rehabilitation, Percent	(0.50%)	(1.00%)
Effective Income Tax Rate Reconciliation, Other Adjustments, Percent	(1.60%)	0.60%
Effective Income Tax Rate Reconciliation, Percent	18.40%	20.20%