Business and Credit Concentrations - Additional Information (Detail) (USD $)	Dec. 31, 2014	Dec. 31, 2013
Concentration Risk [Line Items]
Cash reserve deposit required	$ 250,000	$ 250,000

Cash deposited in a special reserve account for the exclusive benefit of customers pursuant to SEC Regulations.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 305

-Section 50

-Paragraph 1

-URI http://asc.fasb.org/extlink&oid=6478312&loc=d3e61473-112792

Name:	us-gaap_CashReserveDepositRequiredAndMade
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant