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Stockholders' Equity - Changes in Accumulated Other Comprehensive Income (Loss), Net of Tax by Component (Detail) - USD ($) $ in Thousands | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2019 | Jun. 30, 2018 | Jun. 30, 2019 | Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | $ 443,547 | $ 475,736 | $ 446,279 | $ 497,911
Other comprehensive income (loss) before reclassifications | 713 | (3,506) | (216) | (2,921)
Amounts reclassified from accumulated other comprehensive income (loss) | 77 | 191 | 152 | 318
Amounts reclassified to retained earnings |  |  | 385 | (3,220)
Net current period other comprehensive income (loss) | 790 | (3,315) | 321 | (5,823)
Ending Balance | 445,975 | 459,627 | 445,975 | 459,627
ASU 2018-02 [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | 385 |  |  |
Amounts reclassified to retained earnings |  |  | 385 |
Net current period other comprehensive income (loss) |  |  | 385 |
Ending Balance | 385 |  | 385 |
Unrealized Gains (Losses) on Available-for-Sale Securities [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | (378) | (845) | (563) | 2,567
Other comprehensive income (loss) before reclassifications | 180 | (82) | 411 | (339)
Amounts reclassified from accumulated other comprehensive income (loss) | (73) | 186 | (119) | 251
Amounts reclassified to retained earnings |  |  |  | (3,220)
Net current period other comprehensive income (loss) | 107 | 104 | 292 | (3,308)
Ending Balance | (271) | (741) | (271) | (741)
Defined Benefit Plan Adjustments [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | (7,920) | (4,224) | (8,041) | (4,286)
Amounts reclassified from accumulated other comprehensive income (loss) | 150 | 5 | 271 | 67
Net current period other comprehensive income (loss) | 150 | 5 | 271 | 67
Ending Balance | (7,770) | (4,219) | (7,770) | (4,219)
Foreign Currency Adjustments [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | (6,972) | (734) | (5,812) | (1,576)
Other comprehensive income (loss) before reclassifications | 533 | (3,424) | (627) | (2,582)
Net current period other comprehensive income (loss) | 533 | (3,424) | (627) | (2,582)
Ending Balance | (6,439) | (4,158) | (6,439) | (4,158)
Accumulated Other Comprehensive Income [Member] |  |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |  |
Beginning Balance | (14,885) | (5,803) | (14,416) | (3,295)
Ending Balance | $ (14,095) | $ (9,118) | $ (14,095) | $ (9,118)

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