Long-Term Debt - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Mar. 04, 2013
Line of Credit Facility [Line Items]
Amended Maximum Borrowing Capacity		$ 50.0
Maximum Borrowing Capacity		85.0
Maturity Date	Nov. 30, 2014
Accelerated Maturity Date, In The Event of Default	May 31, 2014
Capitalized financing fee written off	0.4
U.S. real estate facilities [Member]
Line of Credit Facility [Line Items]
US Real Estate Facility, Term	15 years
Mortgage Loans	$ 14.1
Number of transportation terminals	10
Minimum [Member] | U.S. real estate facilities [Member]
Line of Credit Facility [Line Items]
Interest rate	4.625%
Interest rate adjustment period	3 years
Maximum [Member] | U.S. real estate facilities [Member]
Line of Credit Facility [Line Items]
Interest rate	4.875%
Interest rate adjustment period	5 years