Stock Based Awards and Other Equity Instruments - Summary of RSU Activity on Common Stock (Parenthetical) (Detail) (Restricted Stock Units (RSUs) [Member])	9 Months Ended
Sep. 30, 2013
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
RSUs withheld to satisfy minimum tax withholding requirements	127,199

For net-share settlement of share-based awards when the employer settles employees' income tax withholding obligations, this element represents the number of shares the employees use to repay the employer.

No definition available.

Name:	us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration