Income Taxes Income Tax Rate Reconciliation (Details)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Statutory Federal income tax rate	21.00%	35.00%	35.00%
State and local income tax, net of Federal tax benefit	9.60%	6.90%	5.60%
Book versus tax difference	6.70%	0.00%	0.00%
Tax-exempt interest, net	(4.80%)	(10.30%)	(7.50%)
Tax credits	(2.90%)	(3.10%)	(2.20%)
Investments in affordable housing projects	1.90%	2.20%	0.90%
Noncontrolling interests	(0.50%)	(1.50%)	(1.40%)
Re-measurement of deferred tax assets and liabilities	0.00%	13.70%	0.00%
Nondeductible goodwill	0.00%	10.10%	0.00%
Other, net	0.40%	0.50%	0.20%
Effective income tax rate	31.40%	53.50%	30.60%