Income Taxes (Reconciliation Between the Federal Statutory Corporate Tax Rate and the Bancorp's Effective Tax Rate) (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation Of Statutory Federal Tax Rate
Statutory tax rate	21.00%	35.00%	35.00%
State taxes, net of federal benefit	2.10%	1.50%	1.20%
Tax-exempt income	(0.80%)	(1.10%)	(2.50%)
LIHTC investment and other tax benefits	(6.80%)	(6.90%)	(9.40%)
LIHTC investment proportional amortization	5.60%	7.40%	6.90%
Other tax credits	(0.10%)	(0.40%)	(0.80%)
U.S. tax legislation impact on deferred taxes	0.00%	(8.50%)	0.00%
Other, net	(0.30%)	(0.20%)	(0.30%)
Effective tax rate	20.70%	26.80%	30.10%