Loans and Leases - Troubled Debt Restructurings, Disaggregated by Type of Concession and by Loan Type (Detail) - USD ($)
$ in Thousands |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
| Financing Receivable, Modifications [Line Items] |
|
|
|
| Non-Accrual TDRs, Deferral of Principal |
$ 2,877
|
$ 1,828
|
$ 3,131
|
| Non-Accrual TDRs, Deferral of Principal and Interest |
3,884
|
4,444
|
1,329
|
| Non-Accrual TDRs, Reduction of Principal and Interest |
1,237
|
212
|
1,329
|
| Non-Accrual TDRs, Extension of Maturity |
102
|
419
|
1,089
|
| Non-Accrual TDRs, Total |
8,100
|
6,903
|
6,878
|
| Accrual TDRs, Deferral of Principal |
3,415
|
4,817
|
4,241
|
| Accrual TDRs, Deferral of Principal and Interest |
182
|
198
|
214
|
| Accrual TDRs, Reduction of Principal and Interest |
1,998
|
3,768
|
3,222
|
| Accrual TDRs, Extension of Maturity |
1,664
|
2,363
|
2,622
|
| Accrual TDRs |
7,259
|
11,146
|
10,299
|
| Real estate loans [Member] |
|
|
|
| Financing Receivable, Modifications [Line Items] |
|
|
|
| Non-Accrual TDRs, Deferral of Principal |
1,935
|
1,679
|
2,864
|
| Non-Accrual TDRs, Deferral of Principal and Interest |
3,761
|
4,373
|
1,329
|
| Non-Accrual TDRs, Reduction of Principal and Interest |
64
|
143
|
216
|
| Non-Accrual TDRs, Extension of Maturity |
0
|
0
|
352
|
| Non-Accrual TDRs, Total |
5,760
|
6,195
|
4,761
|
| Accrual TDRs, Deferral of Principal |
3,409
|
4,795
|
3,951
|
| Accrual TDRs, Deferral of Principal and Interest |
0
|
0
|
0
|
| Accrual TDRs, Reduction of Principal and Interest |
1,387
|
1,514
|
1,549
|
| Accrual TDRs, Extension of Maturity |
1,237
|
1,633
|
1,677
|
| Accrual TDRs |
6,033
|
7,942
|
7,177
|
| Real estate loans [Member] | Retail [Member] |
|
|
|
| Financing Receivable, Modifications [Line Items] |
|
|
|
| Non-Accrual TDRs, Deferral of Principal |
0
|
0
|
0
|
| Non-Accrual TDRs, Deferral of Principal and Interest |
0
|
0
|
0
|
| Non-Accrual TDRs, Reduction of Principal and Interest |
0
|
0
|
0
|
| Non-Accrual TDRs, Extension of Maturity |
0
|
0
|
344
|
| Non-Accrual TDRs, Total |
0
|
0
|
344
|
| Accrual TDRs, Deferral of Principal |
0
|
0
|
0
|
| Accrual TDRs, Deferral of Principal and Interest |
0
|
0
|
0
|
| Accrual TDRs, Reduction of Principal and Interest |
1,188
|
1,228
|
1,227
|
| Accrual TDRs, Extension of Maturity |
0
|
|
0
|
| Accrual TDRs |
1,188
|
1,228
|
1,227
|
| Real estate loans [Member] | Hotel/motel [Member] |
|
|
|
| Financing Receivable, Modifications [Line Items] |
|
|
|
| Non-Accrual TDRs, Deferral of Principal |
1,156
|
1,292
|
1,216
|
| Non-Accrual TDRs, Deferral of Principal and Interest |
3,495
|
3,722
|
28
|
| Non-Accrual TDRs, Reduction of Principal and Interest |
0
|
0
|
0
|
| Non-Accrual TDRs, Extension of Maturity |
0
|
0
|
0
|
| Non-Accrual TDRs, Total |
4,651
|
5,014
|
1,244
|
| Accrual TDRs, Deferral of Principal |
0
|
0
|
414
|
| Accrual TDRs, Deferral of Principal and Interest |
0
|
0
|
0
|
| Accrual TDRs, Reduction of Principal and Interest |
169
|
0
|
0
|
| Accrual TDRs, Extension of Maturity |
0
|
|
0
|
| Accrual TDRs |
169
|
0
|
414
|
| Real estate loans [Member] | Other [Member] |
|
|
|
| Financing Receivable, Modifications [Line Items] |
|
|
|
| Non-Accrual TDRs, Deferral of Principal |
779
|
387
|
959
|
| Non-Accrual TDRs, Deferral of Principal and Interest |
266
|
651
|
1,301
|
| Non-Accrual TDRs, Reduction of Principal and Interest |
64
|
143
|
216
|
| Non-Accrual TDRs, Extension of Maturity |
0
|
0
|
8
|
| Non-Accrual TDRs, Total |
1,109
|
1,181
|
2,484
|
| Accrual TDRs, Deferral of Principal |
2,777
|
4,012
|
3,537
|
| Accrual TDRs, Deferral of Principal and Interest |
0
|
|
0
|
| Accrual TDRs, Reduction of Principal and Interest |
30
|
286
|
322
|
| Accrual TDRs, Extension of Maturity |
959
|
1,344
|
1,378
|
| Accrual TDRs |
3,766
|
5,642
|
5,237
|
| Real estate loans [Member] | Residential property [Member] |
|
|
|
| Financing Receivable, Modifications [Line Items] |
|
|
|
| Non-Accrual TDRs, Deferral of Principal |
0
|
0
|
689
|
| Non-Accrual TDRs, Deferral of Principal and Interest |
0
|
|
0
|
| Non-Accrual TDRs, Reduction of Principal and Interest |
0
|
|
0
|
| Non-Accrual TDRs, Extension of Maturity |
0
|
|
0
|
| Non-Accrual TDRs, Total |
0
|
0
|
689
|
| Accrual TDRs, Deferral of Principal |
632
|
783
|
0
|
| Accrual TDRs, Deferral of Principal and Interest |
0
|
|
0
|
| Accrual TDRs, Reduction of Principal and Interest |
0
|
0
|
0
|
| Accrual TDRs, Extension of Maturity |
278
|
289
|
299
|
| Accrual TDRs |
910
|
1,072
|
299
|
| Commercial and industrial loans [Member] | Commercial term [Member] |
|
|
|
| Financing Receivable, Modifications [Line Items] |
|
|
|
| Non-Accrual TDRs, Deferral of Principal |
131
|
149
|
45
|
| Non-Accrual TDRs, Deferral of Principal and Interest |
123
|
71
|
0
|
| Non-Accrual TDRs, Reduction of Principal and Interest |
1,173
|
69
|
997
|
| Non-Accrual TDRs, Extension of Maturity |
102
|
419
|
679
|
| Non-Accrual TDRs, Total |
1,529
|
708
|
1,721
|
| Accrual TDRs, Deferral of Principal |
6
|
22
|
40
|
| Accrual TDRs, Deferral of Principal and Interest |
182
|
198
|
214
|
| Accrual TDRs, Reduction of Principal and Interest |
503
|
2,135
|
1,673
|
| Accrual TDRs, Extension of Maturity |
427
|
662
|
945
|
| Accrual TDRs |
1,118
|
3,017
|
2,872
|
| Commercial and industrial loans [Member] | Commercial lines of credit [Member] |
|
|
|
| Financing Receivable, Modifications [Line Items] |
|
|
|
| Non-Accrual TDRs, Deferral of Principal |
|
0
|
222
|
| Non-Accrual TDRs, Deferral of Principal and Interest |
|
|
0
|
| Non-Accrual TDRs, Reduction of Principal and Interest |
|
0
|
0
|
| Non-Accrual TDRs, Extension of Maturity |
|
0
|
58
|
| Non-Accrual TDRs, Total |
|
0
|
280
|
| Accrual TDRs, Deferral of Principal |
|
0
|
0
|
| Accrual TDRs, Deferral of Principal and Interest |
|
|
0
|
| Accrual TDRs, Reduction of Principal and Interest |
|
|
0
|
| Accrual TDRs, Extension of Maturity |
|
68
|
0
|
| Accrual TDRs |
|
68
|
0
|
| Consumer loans [Member] |
|
|
|
| Financing Receivable, Modifications [Line Items] |
|
|
|
| Non-Accrual TDRs, Deferral of Principal |
811
|
|
0
|
| Non-Accrual TDRs, Deferral of Principal and Interest |
0
|
|
0
|
| Non-Accrual TDRs, Reduction of Principal and Interest |
0
|
0
|
116
|
| Non-Accrual TDRs, Extension of Maturity |
0
|
|
0
|
| Non-Accrual TDRs, Total |
811
|
0
|
116
|
| Accrual TDRs, Deferral of Principal |
0
|
0
|
250
|
| Accrual TDRs, Deferral of Principal and Interest |
0
|
|
0
|
| Accrual TDRs, Reduction of Principal and Interest |
108
|
119
|
0
|
| Accrual TDRs, Extension of Maturity |
0
|
|
0
|
| Accrual TDRs |
$ 108
|
$ 119
|
$ 250
|