Taxation - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Income Tax Examination [Line Items]
Effective income tax rate	17.30%	33.50%
Unrecognized tax benefits			$ 2.2
Unrecognized tax benefits due to the expiration of statutes of limitation	$ 2.2
Description of income tax examination	The Company's operating subsidiaries in specific countries may be subject to audit by various tax authorities and may have different statutes of limitations expiration dates. With limited exceptions, the Company's major subsidiaries that operate in the United States, United Kingdom and Australia are no longer subject to tax examinations for years before 2010, 2010 and 2007, respectively.
Bermuda [Member]
Income Tax Examination [Line Items]
Effective income tax rate	0.00%