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Comprehensive Income - Schedule of Changes in Balances of Each Component of Accumulated Other Comprehensive Income (Detail) - Successor [Member] - USD ($) $ in Thousands | 12 Months Ended
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Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
Beginning Balance | $ (38,990) | $ 15,215 |
Other comprehensive income before reclassifications | (20,114) | (35,709) |
Amounts reclassified from accumulated other comprehensive income | 13,453 | (18,496) |
Income Tax Expense (Benefit) | (44,464) | (30,709) | $ (17,364)
Net current period other comprehensive income | (13,249) | (54,205) |
Ending Balance | (52,239) | (38,990) | 15,215
Unrealized Gains (Losses) on Available-for-Sale Securities [Member] |  |  |
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
Beginning Balance | 118,863 | 50,963 |
Other comprehensive income before reclassifications | (96,325) | 85,378 |
Amounts reclassified from accumulated other comprehensive income | 14,805 | (17,478) |
Net current period other comprehensive income | (88,108) | 67,900 |
Ending Balance | 30,755 | 118,863 | 50,963
Accumulated Translation Adjustment [Member] |  |  |
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
Beginning Balance | (167,220) | (45,092) |
Other comprehensive income before reclassifications | 73,586 | (122,128) |
Amounts reclassified from accumulated other comprehensive income | 0 | 0 |
Net current period other comprehensive income | 73,586 | (122,128) |
Ending Balance | (93,634) | (167,220) | (45,092)
Other Postretirement Benefits Plan [Member] |  |  |
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
Beginning Balance | 9,367 | 9,344 |
Other comprehensive income before reclassifications | 2,625 | 1,041 |
Amounts reclassified from accumulated other comprehensive income | (1,352) | (1,018) |
Net current period other comprehensive income | 1,273 | 23 |
Ending Balance | 10,640 | $ 9,367 | $ 9,344
Accounting Standards Update 2016-09 [Member] |  |  |
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | 0 |  |
Accounting Standards Update 2016-09 [Member] | Retained Earnings [Member] |  |  |
Changes In Accumulated Other Comprehensive Income [Roll Forward] |  |  |
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification | $ (6,588) |  |

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- Definition Net of tax amount of other comprehensive income (loss) excluding noncontrolling interest. + References No definition available. + Details
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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://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 11 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e637-108580 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14 -URI http://asc.fasb.org/extlink&oid=84228862&loc=d3e681-108580 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580 + Details
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- Definition Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 740 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a),(b) -URI http://asc.fasb.org/extlink&oid=84230637&loc=d3e32639-109319 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(h)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 + Details
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- Definition Amount after tax, before reclassification adjustments of other comprehensive income (loss). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 55 -Paragraph 15 -URI http://asc.fasb.org/extlink&oid=84158357&loc=d3e1436-108581 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=84228862&loc=SL7669686-108580 + Details
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