Retirement Plan - Additional Information (Detail)	12 Months Ended
Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Retirement plan, employees maximum pre-tax contributions percentage	60.00%

Maximum percentage of employee gross pay, by the terms of the plan, that the employer may contribute to a defined contribution plan.

No definition available.

Name:	us-gaap_DefinedContributionPlanMaximumAnnualContributionPerEmployeePercent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration