Summary of Significant Accounting Policies - Depreciable Lives of Premises and Equipment (Details)	12 Months Ended
	Dec. 31, 2019
Minimum | Building [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, depreciable lives	30 years
Minimum | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, depreciable lives	3 years
Minimum | Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, depreciable lives	5 years
Maximum | Building [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, depreciable lives	30 years
Maximum | Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, depreciable lives	12 years
Maximum | Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Premises and equipment, depreciable lives	10 years