Taxation - Additional Information (Detail) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Effective tax rate	14.50%	24.20%	13.30%	18.80%
Statutory rate	0.00%	0.00%	0.00%	0.00%
Increase in deferred tax asset valuation allowance	$ 1,300,000		$ 2,200,000
Unrecognized tax benefits	$ 0		$ 0		$ 0