Income Taxes - Components of Net Deferred Income Tax Asset and Liability (Parenthetical) (Detail) (USD $)	Dec. 31, 2012	Dec. 31, 2011
Schedule Of Income Taxes [Line Items]
Total noncurrent deferred tax liabilities, net	$ 20,784,000	$ 5,963,000
Other assets [Member]
Schedule Of Income Taxes [Line Items]
Total noncurrent deferred tax liabilities, net	148
Other long-term liabilities [Member]
Schedule Of Income Taxes [Line Items]
Total noncurrent deferred tax liabilities, net	$ 20,932	$ 5,963