Income Taxes - Summary of Income Taxes (Federal Statutory Corporate Tax Rate) (Detail)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Abstract]
U.S. Federal statutory rate	21.00%	35.00%	35.00%
Foreign tax credits, net of valuation allowance	(154.90%)	(136.10%)	(61.50%)
Non-taxable foreign income	(48.80%)	(20.10%)	(20.70%)
Foreign tax rate differential	(20.80%)	(17.00%)	(14.50%)
Global intangible low-taxed income	28.30%	0.00%	0.00%
Change in tax rate	0.00%	(11.80%)	0.00%
Repatriation of foreign earnings	0.00%	81.00%	51.60%
Valuation allowance, other	9.30%	5.90%	7.50%
Other, net	3.20%	4.40%	5.20%
Effective income tax rate	(162.70%)	(58.70%)	2.60%