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) - Residential mortgage-backed securities	3 Months Ended
	Mar. 31, 2016
Fair Value Assets Measured On Recurring Basis
Valuation technique to measure fair value	Discounted cash flow
Prepayment rate, Weighted Average of unobservable inputs	10.80%
Default rate, Weighted Average of unobservable inputs	8.40%
Loss severity, Weighted Average of unobservable inputs	59.50%
Minimum
Fair Value Assets Measured On Recurring Basis
Prepayment rate, Range of unobservable inputs	0.10%
Default rate, Range of unobservable inputs	3.70%
Loss severity, Range of unobservable inputs	41.40%
Maximum
Fair Value Assets Measured On Recurring Basis
Prepayment rate, Range of unobservable inputs	22.20%
Default rate, Range of unobservable inputs	20.60%
Loss severity, Range of unobservable inputs	64.60%