Comprehensive Income/(Loss) - Schedule of Amounts Reclassified from Accumulated Other Comprehensive Income (Detail) - USD ($)
$ in Thousands |
3 Months Ended |
Mar. 31, 2018 |
Mar. 31, 2017 |
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |
|
|
| Net securities gains (Non-interest income) |
$ 39
|
$ (12)
|
| Interest and dividends on securities (Interest and dividend income) |
(16,377)
|
(14,487)
|
| Employee benefits (Non-interest expense) |
6,912
|
8,210
|
| Provision for income taxes |
7,004
|
10,622
|
| Net effect on accumulated other comprehensive income for the period |
387
|
605
|
| Accumulated Unrealized Gains on Debt Securities Transferred from Available For Sale to Held to Maturity [Member] |
|
|
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |
|
|
| Net effect on accumulated other comprehensive income for the period |
(50)
|
(50)
|
| Accumulated Defined Benefit Plans Adjustment [Member] |
|
|
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |
|
|
| Net effect on accumulated other comprehensive income for the period |
437
|
655
|
| Amounts Reclassified From Accumulated Other Comprehensive Income/(Loss) [Member] | Accumulated Unrealized Gains (Losses) on Debt Securities Available for Sale [Member] |
|
|
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |
|
|
| Net securities gains (Non-interest income) |
0
|
0
|
| Amounts Reclassified From Accumulated Other Comprehensive Income/(Loss) [Member] | Accumulated Unrealized Gains on Debt Securities Transferred from Available For Sale to Held to Maturity [Member] |
|
|
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |
|
|
| Interest and dividends on securities (Interest and dividend income) |
(66)
|
(72)
|
| Provision for income taxes |
16
|
22
|
| Amounts Reclassified From Accumulated Other Comprehensive Income/(Loss) [Member] | Accumulated Defined Benefit Plans Adjustment [Member] |
|
|
| Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |
|
|
| Employee benefits (Non-interest expense) |
756
|
801
|
| Provision for income taxes |
$ (319)
|
$ (146)
|