Defined Contribution Plan - Additional Information (Detail)	12 Months Ended
Dec. 31, 2012
Defined Contribution Plan [Line Items]
Employer matching contribution, percent	50.00%

Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan.

No definition available.

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