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Changes in Accumulated Other Comprehensive Loss - Reclassifications Out of Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Sep. 30, 2019 | Sep. 30, 2018 | Sep. 30, 2019 | Sep. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |  |  |
Income before provision for income taxes | $ 1,547 | $ 2,005 | $ 1,654 | $ 5,030
Provision for income taxes | 342 | 178 | 367 | 880
Net income | 1,205 | 1,827 | 1,287 | 4,150
Reclassifications Out of Accumulated Other Comprehensive Loss [Member] | Amortization of Actuarial Loss [Member] |  |  |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |  |  |
Income before provision for income taxes | (249) | (218) | (498) | (437)
Reclassifications Out of Accumulated Other Comprehensive Loss [Member] | Pension and Other Postretirement Benefits Items [Member] |  |  |  |
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |  |  |
Provision for income taxes | (54) | (48) | (109) | (97)
Net income | $ (195) | $ (170) | $ (389) | $ (340)

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