Commitments, Contingencies and Off-Balance Sheet Risk - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Maximum period of commitments to make loans	1 year
Maximum time period of maturities	30 years
Average reserve balance under Federal Reserve Board requirements	$ 31,889	$ 2,448
Minimum [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Range of fixed interest rate loan commitments	3.25%	3.25%
Maximum [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]
Range of fixed interest rate loan commitments	8.75%	8.75%