INVESTMENT SECURITIES - Significant Assumptions in Valuation of Private Label MBS (Detail)	Sep. 30, 2012	Dec. 31, 2011
Schedule of Trading Securities and Other Trading Assets [Line Items]
Weighted Average, Discount Rate	14.50%	14.50%
Weighted Average, Prepayment Rate	33.00%	27.00%
Weighted Average, Projected Cumulative Loss Rate	7.00%	6.00%
Percentage of Discount Rate	14.50%	14.50%
Minimum, Prepayment Rate	23.81%	21.33%
Maximum, Prepayment Rate	43.58%	37.97%
Minimum, Projected Cumulative Loss Rate	0.71%	1.94%
Maximum, Projected Cumulative Loss Rate	17.51%	11.89%

Percentage of discount rate on mortgage backed securities.

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Percentage of maximum prepayment rate on mortgage backed securities.

No definition available.

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Percentage of maximum projected cumulative loss rate on mortgage backed securities.

No definition available.

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Percentage of minimum prepayment rate on mortgage backed securities.

No definition available.

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Percentage of minimum projected cumulative loss rate on mortgage backed securities.

No definition available.

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Weighted average discount rate on mortgage backed securities.

No definition available.

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Weighted average prepayment rate on mortgage backed securities.

No definition available.

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Weighted average projected cumulative loss rate on mortgage backed securities.

No definition available.

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