Taxation - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Examination [Line Items]
Effective income tax rate (percent)	18.00%	12.30%	5.10%
Valuation allowance	$ 367,991,000	$ 408,394,000
Unrecognized tax benefits due to expiration of the statute of limitations	2,200,000	0	$ 200,000
Accrued interest and penalties related to unrecognized tax benefits	$ 0	0	$ 700,000
Bermuda
Income Tax Examination [Line Items]
Effective income tax rate (percent)	0.00%
Foreign Tax Authority
Income Tax Examination [Line Items]
Valuation allowance	$ 368,000,000	$ 408,400,000