INVESTMENTS (Amortized Cost and Estimated Fair Values of investment securities Available-For-Sale by Contractual Maturity) (Detail) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Amortized Cost
Due in one year or less	$ 1,605	$ 301
Due after one year through five years	163,105	157,710
Due after five years through ten years	293,974	168,136
Due after ten years	225,192	253,792
Total debt securities available for sale	683,876	579,939
Estimated Fair Value
Due in one year or less	1,623	306
Due after one year through five years	169,257	160,257
Due after five years through ten years	304,116	174,677
Due after ten years	228,653	255,586
Estimated Fair Value	$ 703,649	$ 590,826