Retirement Plans and Related Post Retirement Benefits - Summarizes the Components of the Net Periodic Cost (Detail) - USD ($) $ in Thousands |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| SERP | |||
| Net Periodic Cost | |||
| Service Cost — Benefits Earned During Period | $ 173 | $ 194 | $ 247 |
| Interest Cost | 901 | 843 | 721 |
| Amortization of Prior Service Cost | 413 | 495 | 495 |
| Amortization of Losses | 343 | 449 | 108 |
| Net Periodic Cost | 1,830 | 1,981 | 1,571 |
| SERP Medical | |||
| Net Periodic Cost | |||
| Service Cost — Benefits Earned During Period | 5 | 6 | 3 |
| Interest Cost | 40 | 39 | 31 |
| Amortization of Prior Service Cost | 24 | 26 | 25 |
| Amortization of Losses | 22 | 26 | 0 |
| Net Periodic Cost | $ 91 | $ 97 | $ 59 |
| X | ||||||||||
- Definition The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available.
|
| X | ||||||||||
- Definition Amount included in accumulated other comprehensive income (AOCI) related to gain (loss) expected to be recognized as components of net periodic benefit cost for the fiscal year that follows the most recent annual statement of financial position. No definition available.
|
| X | ||||||||||
- Definition The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Definition The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|