INVESTMENT SECURITIES - Significant Assumptions in Valuation of Private Label MBS (Detail)	3 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Schedule Of Investments [Line Items]
Fair Value Inputs Discount Rate	14.50%	14.50%
Fair Value Inputs Prepayment Rate	31.00%	29.00%
Weighted Average, Projected Cumulative Loss Rate	7.60%	6.80%
Minimum [Member]
Schedule Of Investments [Line Items]
Fair Value Inputs Prepayment Rate	19.21%	15.86%
Weighted Average, Projected Cumulative Loss Rate	0.94%	0.58%
Maximum [Member]
Schedule Of Investments [Line Items]
Fair Value Inputs Prepayment Rate	100.00%	100.00%
Weighted Average, Projected Cumulative Loss Rate	80.00%	38.16%