Summary of Significant Accounting Policies - Premises and Equipment (Narrative)(Details)	12 Months Ended
	Dec. 31, 2012
Bank building [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	40 years
Leasehold improvements [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	30 years
Leasehold improvements [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	1 year
Furniture, fixtures and equipment [Member] | Maximum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	13 years
Furniture, fixtures and equipment [Member] | Minimum [Member]
Property, Plant and Equipment [Line Items]
Useful life (in years)	3 years