Nature of Business and Its Significant Accounting Policies - Bank Premises and Equipment and Depreciation (Details)	12 Months Ended
Dec. 31, 2019
Premises and equipment \| Minimum
Bank Premises and Equipment and Depreciation
Estimated useful lives	2 years
Premises and equipment \| Maximum
Bank Premises and Equipment and Depreciation
Estimated useful lives	50 years
Computer software \| Minimum
Bank Premises and Equipment and Depreciation
Estimated useful lives	3 years
Computer software \| Maximum
Bank Premises and Equipment and Depreciation
Estimated useful lives	5 years

Useful life of long lived, physical assets used in the normal conduct of business and not intended for resale, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. Examples include, but not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

No definition available.

Name:	us-gaap_PropertyPlantAndEquipmentUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration