INVESTMENT SECURITIES - Summary of Amortized Cost and Fair Value - Available-for-Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Amortized Cost
Due in one year or less	$ 5,670
Due after one year through five years	19,456
Due after five years through ten years	3,929
Due after ten years	1,695
Mortgage-backed securities and collateralized mortgage obligations: Residential	279,013
Mortgage-backed securities and collateralized mortgage obligations: Commercial	5,512
Mutual funds	2,100
Amortized Cost	317,375	$ 272,588
Fair Value
Due in one year or less	5,702
Due after one year through five years	20,002
Due after five years through ten years	4,118
Due after ten years	1,671
Mortgage-backed securities and collateralized mortgage obligations: Residential	279,126
Mortgage-backed securities and collateralized mortgage obligations: Commercial	5,448
Mutual funds	2,092
Fair Value	$ 318,159	$ 276,984