| Compensation and Retirement Disclosure [Abstract] | Period [Axis] |
|---|
2015-04-01 - 2016-03-31 |
|---|
Compensation and Retirement Disclosure [Abstract] | |
Components of net postretirement medical expense | The components of net postretirement medical expense for the Officer Medical Plan were as follows: | | | | | | | | | | | | | | | | Fiscal Year Ended March 31, | | | 2016 | | 2015 | | 2014 | Service cost | | $ | 5,702 |
| | $ | 4,086 |
| | $ | 4,745 |
| Interest cost | | 4,505 |
| | 3,568 |
| | 3,660 |
| Net actuarial loss | | 3,536 |
| | 582 |
| | 2,728 |
| Total postretirement medical expense | | $ | 13,743 |
| | $ | 8,236 |
| | $ | 11,133 |
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Weighted-average discount rate for benefit obligation | The weighted-average discount rate used to determine the year-end benefit obligations was as follows: | | | | | | | | | | | | | Fiscal Year Ended March 31, | | | 2016 | | 2015 | | 2014 | Officer Medical Plan | | 4.25 | % | | 4.25 | % | | 4.75 | % | Retired Officers’ Bonus Plan | | 4.25 | % | | 4.25 | % | | 4.75 | % |
|
Assumed health care cost trend rates | Assumed healthcare cost trend rates for the Officer Medical Plan at March 31, 2016 and 2015 were as follows: | | | | | | | | Pre-65 initial rate | | 2016 | | 2015 | Healthcare cost trend rate assumed for next year | | 7.50 | % | | 7.00 | % | Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) | | 4.50 | % | | 5.00 | % | Year that the rate reaches the ultimate trend rate | | 2024 |
| | 2023 |
|
| | | | | | | | Post-65 initial rate | | 2016 | | 2015 | Healthcare cost trend rate assumed for next year | | 9.00 | % | | 6.75 | % | Rate to which the cost trend rate is assumed to decline (the ultimate trend rate) | | 4.50 | % | | 5.00 | % | Year that the rate reaches the ultimate trend rate | | 2024 |
| | 2023 |
|
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Effect of one-percentage-point change in assumed health care cost trend rates | A one-percentage-point change in assumed healthcare cost trend rates calculated as of March 31, 2016 would have the following effects: | | | | | | | | | | | | 1% Increase | | 1% Decrease | Effect on total of service and interest cost | | $ | 2,331 |
| | $ | (1,791 | ) | Effect on postretirement benefit obligation | | 20,459 |
| | (16,291 | ) |
|
Change in Benefit Obligation | The changes in the benefit obligation, plan assets, and funded status of the Officer Medical Plan were as follows: | | | | | | | | | | | | | | | | Fiscal Year Ended March 31, | | | 2016 | | 2015 | | 2014 | Benefit obligation, beginning of the year | | $ | 107,317 |
| | $ | 75,902 |
| | $ | 78,735 |
| Service cost | | 5,702 |
| | 4,086 |
| | 4,745 |
| Interest cost | | 4,505 |
| | 3,568 |
| | 3,660 |
| Net actuarial (gain) loss | | (496 | ) | | 26,293 |
| | (9,436 | ) | Benefits paid | | (3,020 | ) | | (2,532 | ) | | (1,802 | ) | Benefit obligation, end of the year | | $ | 114,008 |
| | $ | 107,317 |
| | $ | 75,902 |
|
|
Change in fair value of plan assets | | | | | | | | | | | | | | | | | Fiscal Year Ended March 31, | Changes in plan assets | | 2016 | | 2015 | | 2014 | Fair value of plan assets, beginning of the year | | $ | — |
| | $ | — |
| | $ | — |
| Employer contributions | | 3,020 |
| | 2,532 |
| | 1,802 |
| Benefits paid | | (3,020 | ) | | (2,532 | ) | | (1,802 | ) | Fair value of plan assets, end of the year | | $ | — |
| | $ | — |
| | $ | — |
|
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Expected future benefit payments | The expected future medical benefit payments and related contributions are as follows: | | | | | | | For the Fiscal Year Ending March 31, | | 2017 | $ | 3,001 |
| 2018 | $ | 3,414 |
| 2019 | $ | 3,815 |
| 2020 | $ | 4,245 |
| 2021 | $ | 4,625 |
| 2022-2025 | $ | 28,833 |
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