Summary of Significant Accounting Policies - Useful Lives for Premises and Equipment (Details)	12 Months Ended
	Dec. 31, 2016
Buildings and improvements | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives, years	5 years
Buildings and improvements | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives, years	39 years
Furniture and equipment | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives, years	3 years
Furniture and equipment | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives, years	10 years
Computers and software | Minimum
Property, Plant and Equipment [Line Items]
Useful Lives, years	3 years
Computers and software | Maximum
Property, Plant and Equipment [Line Items]
Useful Lives, years	5 years