Goodwill - Additional Information (Detail) (USD $)	9 Months Ended	12 Months Ended
Sep. 30, 2014	Dec. 31, 2013
Goodwill And Intangible Assets Disclosure [Abstract]
Changes in the carrying amount of goodwill		$ 0
Amortization period of acquired goodwill for tax purpose	15 years

Amount of increase (decrease) of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 20

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=35741047&loc=d3e13816-109267

Name:	us-gaap_GoodwillPeriodIncreaseDecrease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration