Accrued Expenses (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule of Accrued Liabilities [Line Items]
Accrued sales and property taxes	$ 8,893	$ 6,141
Accrued salaries and benefits	5,562	2,115
Accrued interest	1,031	806
Other accrued expenses	3,499	6,719
Accrued expenses	$ 18,985	$ 15,781