Changes in the Carrying Amount and Accretable Yield for Acquired Impaired Loans (Detail) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement [Line Items]
Balance at beginning of period, Accretable Yield	$ 1,219	$ 1,417
Accretion, Accretable Yield	(39)	(198)
Payments received, net, Accretable Yield	0	0
Balance at end of period, Accretable Yield	1,180	1,219
Balance at beginning of period, Carrying Amount of Loans	1,821	2,063
Accretion, Carrying Amount of Loans	39	198
Payments received, net, Carrying Amount of Loans	(113)	(440)
Balance at end of period, Carrying Amount of Loans	$ 1,747	$ 1,821