Loans and reserve for credit losses (Schedule of Payment Defaults on Troubled Debt Restructurings on Financing Receivables) (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2013
loan
Dec. 31, 2012
loan
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]    
Number of loans 2 3
TDRs restructured in the period with a payment default $ 3,500 $ 205
Commercial real estate    
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]    
Number of loans 2 0
TDRs restructured in the period with a payment default 3,500 0
Commercial and industrial    
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]    
Number of loans 0 1
TDRs restructured in the period with a payment default 0 193
Consumer    
Troubled Debt Restructuring, Debtor, Subsequent Periods [Line Items]    
Number of loans 0 2
TDRs restructured in the period with a payment default $ 0 $ 12