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Comprehensive Income - Schedule of Changes in Balances of Each Component of Accumulated Other Comprehensive Income (Detail) - USD ($) $ in Thousands | 3 Months Ended |
--- | --- | ---
Mar. 31, 2019 | Mar. 31, 2018 | Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Accumulated Other Comprehensive Income (Loss), Restated |  |  | $ (55,139)
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets |  |  | (2,900)
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
Beginning Balance | $ (48,715) | $ (52,239) |
Other comprehensive income before reclassifications | (88,627) | (156,659) |
Amounts reclassified from accumulated other comprehensive income | (17,370) | (2,044) |
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | 71,257 | 154,615 |
Ending Balance | 22,542 | 99,476 |
Income Tax Expense (Benefit) | 1,991 | 2,605 |
Unrealized Gains (Losses) on Available-for-Sale Securities [Member] |  |  |
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
Beginning Balance | 85,903 | 30,755 |
Other comprehensive income before reclassifications | (73,367) | (125,159) |
Amounts reclassified from accumulated other comprehensive income | (17,204) | (2,855) |
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | 56,163 | 122,304 |
Ending Balance | 142,066 | 153,059 |
Accumulated Translation Adjustment [Member] |  |  |
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
Beginning Balance | (141,527) | (93,634) |
Other comprehensive income before reclassifications | (14,571) | (32,056) |
Amounts reclassified from accumulated other comprehensive income | 0 | 0 |
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | 14,571 | 32,056 |
Ending Balance | (126,956) | (61,578) |
Accumulated Gain (Loss), Financial Liability, Fair Value Option, Attributable to Parent [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets |  |  | $ (2,900)
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
Beginning Balance | (1,965) | (2,900) |
Other comprehensive income before reclassifications | 0 | 0 |
Amounts reclassified from accumulated other comprehensive income | 156 | 1,114 |
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | 156 | 1,114 |
Ending Balance | (1,809) | (1,786) |
Other Postretirement Benefits Plan [Member] |  |  |
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
Beginning Balance | 8,874 | 10,640 |
Other comprehensive income before reclassifications | (689) | 556 |
Amounts reclassified from accumulated other comprehensive income | (322) | (303) |
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | 367 | (859) |
Ending Balance | 9,241 | 9,781 |
Reclassification out of Accumulated Other Comprehensive Income [Member] | Unrealized Gains (Losses) on Available-for-Sale Securities [Member] |  |  |
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
Income Tax Expense (Benefit) | (511) | 1,708 |
Reclassification out of Accumulated Other Comprehensive Income [Member] | Other Postretirement Benefits Plan [Member] |  |  |
Accumulated Other Comprehensive Income (Loss) [Line Items] |  |  |
Other Comprehensive (Income) Loss, Defined Benefit Plan, Prior Service Cost (Credit), Reclassification Adjustment from AOCI, before Tax | (241) | (241) |
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
Amounts reclassified from accumulated other comprehensive income | (322) | (303) |
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax | 81 | 62 |
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest | (322) | (303) |
Income Tax Expense (Benefit) | $ 0 | $ 0 |

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- Definition Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e637-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=114867106&loc=SL7669686-108580 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=114867106&loc=d3e681-108580 + Details
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