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v3.19.1

Changes in Accumulated Other Comprehensive Loss - Reclassifications Out of Accumulated Other Comprehensive Loss by Component (Detail) - USD ($) $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2019 | Dec. 31, 2018 | Sep. 30, 2018 | Jun. 30, 2018 | Mar. 31, 2018 | Dec. 31, 2017 | Sep. 30, 2017 | Jun. 30, 2017 | Mar. 31, 2019 | Mar. 31, 2018 | Mar. 31, 2017
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items] |  |  |  |  |  |  |  |  |  |  |
Income before provision for income taxes |  |  |  |  |  |  |  |  | $ (145) | $ (12,854) | $ 7,049
Provision for income taxes |  |  |  |  |  |  |  |  | 163 | (3,010) | 2,026
Net income | $ (4,553) | $ 95 | $ 1,827 | $ 2,323 | $ 833 | $ (11,622) | $ 10 | $ 935 | (308) | (9,844) | $ 5,023
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 |  |  |  |  |  |  |  |  | (875) | (1,050) |
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] |  |  |  |  |  |  |  |  |  |  |
Income before provision for income taxes |  |  |  |  |  |  |  |  | (875) | (1,050) |
Provision for income taxes |  |  |  |  |  |  |  |  | (142) | (233) |
Net income |  |  |  |  |  |  |  |  | $ (733) | $ (817) |

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