Annual report pursuant to Section 13 and 15(d)

Loans and Leases - Troubled Debt Restructurings, Disaggregated by Loan Class (Detail)

v3.8.0.1
Loans and Leases - Troubled Debt Restructurings, Disaggregated by Loan Class (Detail)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
USD ($)
SecurityLoan
Dec. 31, 2016
USD ($)
SecurityLoan
Dec. 31, 2015
USD ($)
SecurityLoan
Financing Receivable, Modifications [Line Items]      
Number of Loans | SecurityLoan 4 7 14
Pre-Modification Outstanding Recorded Investment $ 1,125 $ 4,188 $ 3,178
Post-Modification Outstanding Recorded Investment $ 1,118 $ 4,076 $ 3,002
Real estate loans [Member]      
Financing Receivable, Modifications [Line Items]      
Number of Loans | SecurityLoan 2 2 3
Pre-Modification Outstanding Recorded Investment $ 182 $ 3,785 $ 1,955
Post-Modification Outstanding Recorded Investment $ 184 $ 3,745 $ 1,951
Real estate loans [Member] | Retail [Member]      
Financing Receivable, Modifications [Line Items]      
Number of Loans | SecurityLoan 0 1 1
Pre-Modification Outstanding Recorded Investment $ 0 $ 21 $ 1,230
Post-Modification Outstanding Recorded Investment $ 0 23 1,227
Loan modifications made through reduction of principal or accrued interest payments   $ 23  
Loan modification made through deferrals principal payment     $ 1,200
Real estate loans [Member] | Hotel/motel [Member]      
Financing Receivable, Modifications [Line Items]      
Number of Loans | SecurityLoan 1 1 0
Pre-Modification Outstanding Recorded Investment $ 167 $ 3,764 $ 0
Post-Modification Outstanding Recorded Investment 169 3,722 $ 0
Loan modifications made through reduction of principal or accrued interest payments $ 169    
Loan modification made through deferrals principal payment   $ 3,700  
Real estate loans [Member] | Other [Member]      
Financing Receivable, Modifications [Line Items]      
Number of Loans | SecurityLoan 1 0 2
Pre-Modification Outstanding Recorded Investment $ 15 $ 0 $ 725
Post-Modification Outstanding Recorded Investment 15 $ 0 724
Loan modification made through deferrals principal payment $ 15   $ 724
Commercial and industrial loans [Member] | Commercial term [Member]      
Financing Receivable, Modifications [Line Items]      
Number of Loans | SecurityLoan 1 5 10
Pre-Modification Outstanding Recorded Investment $ 123 $ 403 $ 973
Post-Modification Outstanding Recorded Investment 123 331 801
Loan modifications made through reduction of principal or accrued interest payments   65 60
Loan modification made through deferrals principal payment $ 123 216 34
Amount of loan modification through extension of maturity   $ 50 $ 707
Consumer loans [Member]      
Financing Receivable, Modifications [Line Items]      
Number of Loans | SecurityLoan 1 0 1
Pre-Modification Outstanding Recorded Investment $ 820 $ 0 $ 250
Post-Modification Outstanding Recorded Investment 811 $ 0 250
Loan modification made through deferrals principal payment $ 811   $ 250