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Nature of Business - Changes in Accumulated Other Comprehensive Income (Loss), Net of Tax by Components Of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Beginning Balance | $ 446,279 | $ 497,911 | $ 479,517
Other comprehensive income (loss) before reclassifications | (2,624) | (7,441) | 10,851
Amounts reclassified to retained earnings | 385 | (3,220) |
Amounts reclassified from accumulated other comprehensive loss | 238 | (460) | (1,958)
Ending Balance | 380,426 | 446,279 | 497,911
ASU 2018-02 [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Amounts reclassified to retained earnings | 385 |  |
Ending Balance | 385 |  |
Unrealized Gains (Losses) on Available-for-Sale Securities [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Beginning Balance | (563) | 2,567 | 404
Other comprehensive income (loss) before reclassifications | 573 | 685 | 5,020
Amounts reclassified to retained earnings |  | (3,220) |
Amounts reclassified from accumulated other comprehensive loss | (294) | (595) | (2,857)
Ending Balance | (284) | (563) | 2,567
Unrealized Gains (Losses) on Cash Flow Hedges [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Other comprehensive income (loss) before reclassifications |  |  | (619)
Amounts reclassified from accumulated other comprehensive loss |  |  | 619
Defined Benefit Plan Adjustments [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Beginning Balance | (8,041) | (4,286) | (5,017)
Other comprehensive income (loss) before reclassifications | (1,717) | (3,890) | 451
Amounts reclassified from accumulated other comprehensive loss | 532 | 135 | 280
Ending Balance | (9,226) | (8,041) | (4,286)
Foreign Currency Adjustments [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Beginning Balance | (5,812) | (1,576) | (7,575)
Other comprehensive income (loss) before reclassifications | (1,480) | (4,236) | 5,999
Ending Balance | (7,292) | (5,812) | (1,576)
Accumulated Other Comprehensive Income [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Beginning Balance | (14,416) | (3,295) | (12,188)
Ending Balance | $ (16,417) | $ (14,416) | $ (3,295)

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