INVESTMENTS (Amortized Cost and Estimated Fair Values of investment securities Available-For-Sale by Contractual Maturity) (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Amortized Cost
Due in one year or less	$ 7,493	$ 301
Due after one year through five years	156,953	157,710
Due after five years through ten years	282,468	168,136
Due after ten years	282,708	253,792
Total debt securities available for sale	729,622	579,939
Estimated Fair Value
Due in one year or less	7,541	306
Due after one year through five years	162,233	160,257
Due after five years through ten years	282,713	174,677
Due after ten years	279,844	255,586
Estimated Fair Value	$ 732,331	$ 590,826