INVESTMENT SECURITIES - Schedule of Amortized Cost and Approximate Fair Value of Investment Debt Securities by Contractual Maturity (Including Mortgage-backed Securities) (Detail) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Weighted Average T.E. Yield [Abstract]
Weighted average T.E. yield of securities available-for-sale, due within one year	2.05%	1.61%
Weighted average T.E. yield of securities available-for-sale, due after one year through five years	2.33%	2.27%
Weighted average T.E. yield of securities available-for-sale, due after five years through ten years	2.93%	2.77%
Weighted average T.E. yield of securities available-for-sale, due after ten years	2.53%	2.51%
Available-for-sale Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis [Abstract]
Amortized cost of securities available-for-sale, due within one year	$ 900	$ 1,753
Amortized cost of securities available-for-sale, due after one year through five years	11,641	10,509
Amortized cost of securities available-for-sale, due after five years through ten years	26,963	27,173
Amortized cost of securities available-for-sale, due after ten years	136,148	126,112
Amortized cost of total debt securities	175,652	165,547
Available-for-sale Securities, Debt Maturities, Single Maturity Date [Abstract]
Fair value of securities available-for-sale, due within one year	898	1,750
Fair value of securities available-for-sale, due after one year through five years	11,654	10,476
Fair value of securities available-for-sale, due after five years through ten years	26,611	26,771
Fair value of securities available-for-sale, due after ten years	134,271	123,348
Fair value of total debt securities available-for-sale	$ 173,434	$ 162,345
Held-to-Maturity Securities, Debt Maturities, Single Maturity Date, Weighted Average T.E. Yield [Abstract]
Weighted average T.E. yield of securities held-to-maturity, due within one year	7.17%	7.17%
Weighted average T.E. yield of securities held-to-maturity, due after one year through five years	7.17%	7.17%
Weighted average T.E. yield of securities held-to-maturity, due after five years through ten years	7.17%	7.17%
Weighted average T.E. yield of securities held-to-maturity, due after ten years	3.54%	3.17%
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Amortized Cost Basis [Abstract]
Amortized cost of securities held-to-maturity, due within one year	$ 685	$ 685
Amortized cost of securities held-to-maturity, due after one year through five years	3,095	3,095
Amortized cost of securities held-to-maturity, due after five years through ten years	2,745	2,745
Amortized cost of securities held-to-maturity, due after ten years	13,123	13,566
Amortized cost	19,648	20,091
Held-to-maturity Securities, Debt Maturities, Single Maturity Date, Fair Value [Abstract]
Fair value of securities held-to-maturity, due within one year	686	686
Fair value of securities held-to-maturity, due after one year through five years	3,100	3,089
Fair value of securities held-to-maturity, due after five years through ten years	2,730	2,637
Fair value of securities held-to-maturity, due after ten years	12,906	13,200
Fair value of total debt securities held-to-maturity	$ 19,422	$ 19,612