Income Taxes (Reconciliation of Federal Income Tax Rate to Effective Income Tax Rate) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Abstract]
Federal statutory rate	35.00%	35.00%
Tax-exempt income on securities and loans	(2.80%)	(2.90%)
Tax-exempt BOLI income	(3.40%)	(5.00%)
State income tax, net of federal tax benefit	4.70%	4.50%
Tax credits	(3.40%)	(4.40%)
Tax Reform impact	26.40%	0.00%
Other	0.30%	0.40%
Effective Income Tax Rate Reconciliation, Percent, Total	56.80%	27.60%