Related-Party Transactions - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Related Party Transaction [Line Items]
Terms and conditions of service agreement with Loews	The Services Agreement may be terminated at our option upon 30 days' notice to Loews and at the option of Loews upon six months' notice to us
Services Agreement With Loews [Member]
Related Party Transaction [Line Items]
Related party transaction expenses	$ 0.8	$ 1.1	$ 1.3
SEACOR Holdings Inc [Member]
Related Party Transaction [Line Items]
Related party transaction expenses	0.1	0.1	3.1
Ernst & Young LLP [Member]
Related Party Transaction [Line Items]
Related party transaction expenses	$ 1.0	$ 1.2	$ 1.0