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Stockholders' Equity - Changes in Accumulated Other Comprehensive Loss, Net of Tax by Component (Detail) - USD ($) $ in Thousands | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2021 | Sep. 30, 2020 | Sep. 30, 2021 | Sep. 30, 2020
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | $ 375,515 | $ 364,194 | $ 372,944 | $ 380,426
Other comprehensive income (loss) before reclassifications | (1,418) | 2,963 | (3,272) | 3,162
Amounts reclassified from accumulated other comprehensive income (loss) | 92 | (295) | 445 | 577
Net current period other comprehensive income (loss) | (1,326) | 2,668 | (2,827) | 3,739
Ending Balance | 363,753 | 369,593 | 363,753 | 369,593
ASU 2018-02 [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | 385 | 385 | 385 | 385
Ending Balance | 385 | 385 | 385 | 385
Accumulated Other Comprehensive Loss [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | (13,140) | (15,346) | (11,639) | (16,417)
Ending Balance | (14,466) | (12,678) | (14,466) | (12,678)
Unrealized Gains (Losses) on Available-for-Sale Securities [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | (255) | 206 | 32 | (284)
Other comprehensive income (loss) before reclassifications | (29) | 494 | (358) | 444
Amounts reclassified from accumulated other comprehensive income (loss) | (32) | (539) | 10 | 1
Net current period other comprehensive income (loss) | (61) | (45) | (348) | 445
Ending Balance | (316) | 161 | (316) | 161
Defined Benefit Plan Adjustments [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | (9,310) | (8,894) | (9,621) | (9,226)
Amounts reclassified from accumulated other comprehensive income (loss) | 124 | 244 | 435 | 576
Net current period other comprehensive income (loss) | 124 | 244 | 435 | 576
Ending Balance | (9,186) | (8,650) | (9,186) | (8,650)
Foreign Currency Adjustments [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | (3,960) | (7,043) | (2,435) | (7,292)
Other comprehensive income (loss) before reclassifications | (1,389) | 2,469 | (2,914) | 2,718
Net current period other comprehensive income (loss) | (1,389) | 2,469 | (2,914) | 2,718
Ending Balance | $ (5,349) | $ (4,574) | $ (5,349) | $ (4,574)

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