Fair Value Measurement of Assets and Liabilities - Schedule of Quantitative Information about Level 3 Inputs Used to Measure Fair Value of Available for Sale Securities (Detail) (Significant Unobservable Inputs (Level 3) [Member], Residential Mortgage-Backed Securities [Member])	3 Months Ended
	Mar. 31, 2014
Fair Value Assets Measured On Recurring Basis [Line Items]
Valuation technique to measure fair value	Discounted cash flow
Prepayment rate, Weighted Average of unobservable inputs	19.00%
Default rate, Weighted Average of unobservable inputs	8.00%
Loss severity, Weighted Average of unobservable inputs	49.00%
Minimum [Member]
Fair Value Assets Measured On Recurring Basis [Line Items]
Prepayment rate, Range of unobservable inputs	12.50%
Default rate, Range of unobservable inputs	2.80%
Loss severity, Range of unobservable inputs	40.00%
Maximum [Member]
Fair Value Assets Measured On Recurring Basis [Line Items]
Prepayment rate, Range of unobservable inputs	27.40%
Default rate, Range of unobservable inputs	22.51%
Loss severity, Range of unobservable inputs	52.90%