SECURITIES - Amortized Cost and Fair Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	$ 401,570	$ 203,525
Held for Investment, Fair Value, Total	404,572	202,813
Available for Sale, Amortized Cost, Total	914,712
Available for Sale, Fair Value, Total	923,560	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	8,166
Available for Sale, Fair Value, Due in less than one year	8,324
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	86,415
Available for Sale, Fair Value, Due after one year through five years	86,694
Held for Investment, Amortized Cost, Due after five years through ten years	41,444
Held for Investment, Fair Value, Due after five years through ten years	38,043
Available for Sale, Amortized Cost, Due after five years through ten years	136,999
Available for Sale, Fair Value, Due after five years through ten years	137,851
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	32,736
Available for Sale, Fair Value, Due after ten years	34,544
Held for Investment, Amortized Cost, Total	41,444
Held for Investment, Fair Value, Total	38,043
Available for Sale, Amortized Cost, Total	264,316
Available for Sale, Fair Value, Total	267,413
Mortgage-backed securities of U.S. Government Sponsored Entities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	182,956
Held for Investment, Fair Value, Total	187,024	65,551
Available for Sale, Amortized Cost, Total	202,580
Available for Sale, Fair Value, Total	206,764	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	170,102
Held for Investment, Fair Value, Total	172,758	89,440
Available for Sale, Amortized Cost, Total	282,426
Available for Sale, Fair Value, Total	284,994	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	32,608
Available for Sale, Fair Value, Total	31,886	31,792
Private collateralized mortgage obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	7,068
Held for Investment, Fair Value, Total	6,927	7,882
Available for Sale, Amortized Cost, Total	78,202
Available for Sale, Fair Value, Total	77,748	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	11,289
Available for Sale, Fair Value, Total	77,699	44,273
Private 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	43,291
Available for Sale, Fair Value, Total	$ 43,455	$ 40,420