Summary of Significant Accounting Policies - Concentration Risk - (Details)	12 Months Ended
	Dec. 31, 2016
Securities Issued By Government Sponsored Entities [Member] | Customer Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)	90.00%
Sales Revenue, Product Line [Member] | Commercial Real Estate Loans [Member] | Product Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)	43.00%
Sales Revenue, Product Line [Member] | Commercial and industrial [Member] | Product Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)	18.00%
Sales Revenue, Product Line [Member] | Construction and Development Loans [Member] | Product Concentration Risk [Member]
Concentration Risk [Line Items]
Concentration risk, percentage (in hundredths)	14.00%