Fair Value Measurement - Schedule of Assets Measured at Fair Value on Nonrecurring Basis (Detail) - USD ($)
$ in Thousands |
3 Months Ended |
12 Months Ended |
Mar. 31, 2018 |
Dec. 31, 2017 |
| Fair Value Inputs, Assets, Quantitative Information [Line Items] |
|
|
| Other real estate owned and repossessed assets |
$ 4,067
|
$ 5,297
|
| Impaired loans, Appraisal adjustments |
(4.80%)
|
(4.80%)
|
| Impaired loans, Liquidation expenses |
(7.60%)
|
(7.60%)
|
| Nonrecurring Fair Value Measurements [Member] |
|
|
| Fair Value Inputs, Assets, Quantitative Information [Line Items] |
|
|
| Impaired loans |
$ 1,717
|
$ 1,717
|
| Other real estate owned and repossessed assets |
4,067
|
5,297
|
| Significant Unobservable Inputs (Level 3) [Member] | Nonrecurring Fair Value Measurements [Member] |
|
|
| Fair Value Inputs, Assets, Quantitative Information [Line Items] |
|
|
| Impaired loans |
1,717
|
1,717
|
| Other real estate owned and repossessed assets |
$ 4,067
|
$ 5,297
|
| Weighted Average [Member] |
|
|
| Fair Value Inputs, Assets, Quantitative Information [Line Items] |
|
|
| Impaired loans, Appraisal adjustments |
(4.80%)
|
(4.80%)
|
| Impaired loans, Liquidation expenses |
(7.60%)
|
(7.60%)
|