Summary of Significant Accounting Policies - Additional Information (Detail)	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]
Weighted-average shares subject to repurchase excluded from the weighted-average number of common shares outstanding	94,375	109,375

Number of shares of common stock subject to repurchase or cancellation determined by relating the portion of time within a reporting period that these shares have been outstanding to the total time in that period. Common stock subject to repurchase are outstanding common shares that are contingently returnable (that is, subject to recall).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 260

-SubTopic 10

-Section 45

-Paragraph 13

-URI http://asc.fasb.org/extlink&oid=7655603&loc=d3e2646-109256

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