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])	6 Months Ended
	Jun. 30, 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	14.40%
Default rate, Weighted Average of unobservable inputs	7.90%
Loss severity, Weighted Average of unobservable inputs	48.90%
Minimum [Member]
Fair Value Assets Measured On Recurring Basis [Line Items]
Prepayment rate, Range of unobservable inputs	1.30%
Default rate, Range of unobservable inputs	2.40%
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	44.30%
Default rate, Range of unobservable inputs	22.96%
Loss severity, Range of unobservable inputs	52.90%