Comprehensive Income - Schedule of Changes in Balances of Each Component of Accumulated Other Comprehensive Income (Detail) - Successor [Member] - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ (52,239)	$ (38,990)
Other comprehensive income before reclassifications	156,659	27,718
Amounts reclassified from accumulated other comprehensive income	(2,044)	8,497
Net current period other comprehensive income	154,615	36,215
Ending Balance	99,476	(2,775)
Income Tax Expense (Benefit)	2,605	19,581
Unrealized Gains (Losses) on Available-for-Sale Securities [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	30,755	118,863
Other comprehensive income before reclassifications	125,159	12,500
Amounts reclassified from accumulated other comprehensive income	(2,855)	8,835
Net current period other comprehensive income	122,304	21,335
Ending Balance	153,059	140,198
Accumulated Translation Adjustment [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(93,634)	(167,220)
Other comprehensive income before reclassifications	32,056	12,593
Amounts reclassified from accumulated other comprehensive income	0	0
Net current period other comprehensive income	32,056	12,593
Ending Balance	(61,578)	(154,627)
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	(2,900)
Other comprehensive income before reclassifications	0
Amounts reclassified from accumulated other comprehensive income	1,114
Net current period other comprehensive income	1,114
Ending Balance	(1,786)
Other Postretirement Benefits Plan [Member]
Changes In Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	10,640	9,367
Other comprehensive income before reclassifications	(556)	2,625
Amounts reclassified from accumulated other comprehensive income	(303)	(338)
Net current period other comprehensive income	(859)	2,287
Ending Balance	9,781	11,654
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)	1,708	0
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	(303)	(338)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	62	97
Income (Loss) from Continuing Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest	(303)	(338)
Income Tax Expense (Benefit)	$ 0	$ 0