Payables to Securities Brokers - Additional Information (Detail)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Minimum [Member]
Securities Financing Transaction [Line Items]
Percentage of bearing interest payable to securities brokers	8.00%	8.00%
Maximum [Member]
Securities Financing Transaction [Line Items]
Percentage of bearing interest payable to securities brokers	11.25%	11.25%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration