Income Taxation - Reconciliation of Earnings before Income Taxes Computed by Applying Effective Rate (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Earnings (loss) before income tax	$ 932,656	$ (218,396)	$ 314,411
Bermuda income taxes at statutory rate	0.00%	0.00%	0.00%
Foreign income tax rate differential	8.60%	0.70%	13.10%
Change in valuation allowance	(8.20%)	(0.30%)	(34.90%)
Effect of change in foreign (U.S.) tax rate	0.00%	0.00%	20.30%
U.S. base erosion and anti-abuse tax	0.50%	(0.60%)	0.00%
Other	(0.40%)	3.00%	(0.50%)
Effective tax rate	0.50%	2.80%	(2.00%)