SECURITIES - Amortized Cost and Fair Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	$ 392,138	$ 203,525
Held for Investment, Fair Value, Total	397,264	202,813
Available for Sale, Amortized Cost, Total	858,434
Available for Sale, Fair Value, Total	866,613	790,766
Collateralized Loan Obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Due in less than one year	0
Held for Investment, Fair Value, Due in less than one year	0
Available for Sale Amortized Cost, Due in less than one year	7,760
Available for Sale, Fair Value, Due in less than one year	7,934
Held for Investment, Amortized Cost, Due after one year through five years	0
Held for Investment, Fair Value, Due after one year through five years	0
Available for Sale, Amortized Cost, Due after one year through five years	83,490
Available for Sale, Fair Value, Due after one year through five years	84,017
Held for Investment, Amortized Cost, Due after five years through ten years	41,494
Held for Investment, Fair Value, Due after five years through ten years	41,212
Available for Sale, Amortized Cost, Due after five years through ten years	139,005
Available for Sale, Fair Value, Due after five years through ten years	140,811
Held for Investment, Amortized Cost, Due after ten years	0
Held for Investment, Fair Value, Due after ten years	0
Available for Sale, Amortized Cost, Due after ten years	33,131
Available for Sale, Fair Value, Due after ten years	34,422
Held for Investment, Amortized Cost, Total	41,494
Held for Investment, Fair Value, Total	41,212
Available for Sale, Amortized Cost, Total	263,386
Available for Sale, Fair Value, Total	267,184
Mortgage-backed securities of U.S. Government Sponsored Entities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	183,507
Held for Investment, Fair Value, Total	187,813	65,551
Available for Sale, Amortized Cost, Total	165,802
Available for Sale, Fair Value, Total	168,974	191,749
Collateralized Mortgage Obligations Of US Government Sponsored Entities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	160,377
Held for Investment, Fair Value, Total	161,590	89,440
Available for Sale, Amortized Cost, Total	251,419
Available for Sale, Fair Value, Total	252,483	238,190
Private mortgage backed securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	0
Held for Investment, Fair Value, Total	0
Available for Sale, Amortized Cost, Total	32,720
Available for Sale, Fair Value, Total	32,032	31,792
Private collateralized mortgage obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	6,760
Held for Investment, Fair Value, Total	6,649	7,882
Available for Sale, Amortized Cost, Total	73,371
Available for Sale, Fair Value, Total	73,128	77,957
Corporate and other debt securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	0
Held for Investment, Fair Value, Total	0
Available for Sale, Amortized Cost, Total	11,112
Available for Sale, Fair Value, Total	76,638	44,273
Commercial mortgage backed securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	0
Held for Investment, Fair Value, Total	0
Available for Sale, Amortized Cost, Total	60,624
Available for Sale, Fair Value, Total	$ 61,682	$ 40,420