SECURITIES - Amortized Cost and Fair Value of Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	$ 379,657	$ 372,498
Held for Investment, Fair Value, Total	378,232	369,881
Available for Sale, Amortized Cost, Total	916,406
Available for Sale, Fair Value, Total	909,275	950,503
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	9,533
Available for Sale, Fair Value, Due in less than one year	9,734
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	77,180
Available for Sale, Fair Value, Due after one year through five years	77,564
Held for Investment, Amortized Cost, Due after five years through ten years	26,904
Held for Investment, Fair Value, Due after five years through ten years	27,308
Available for Sale, Amortized Cost, Due after five years through ten years	119,950
Available for Sale, Fair Value, Due after five years through ten years	121,095
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	31,350
Available for Sale, Fair Value, Due after ten years	30,640
Held for Investment, Amortized Cost, Total	26,904
Held for Investment, Fair Value, Total	27,308
Available for Sale, Amortized Cost, Total	238,013
Available for Sale, Fair Value, Total	239,033
Mortgage-backed securities of U.S. Government Sponsored Entities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	188,402
Held for Investment, Fair Value, Total	187,941	159,402
Available for Sale, Amortized Cost, Total	290,933
Available for Sale, Fair Value, Total	287,792	283,488
Collateralized Mortgage Obligations Of US Government Sponsored Entities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	140,786
Held for Investment, Fair Value, Total	139,140	144,964
Available for Sale, Amortized Cost, Total	228,035
Available for Sale, Fair Value, Total	223,642	234,054
Private mortgage backed securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	6,166
Held for Investment, Fair Value, Total	6,084
Available for Sale, Amortized Cost, Total	32,816
Available for Sale, Fair Value, Total	32,165	31,989
Private collateralized mortgage obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	0
Held for Investment, Fair Value, Total	6,084	6,318
Available for Sale, Amortized Cost, Total	61,173
Available for Sale, Fair Value, Total	61,074	67,289
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	10,705
Available for Sale, Fair Value, Total	72,549	73,861
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	32,403
Available for Sale, Fair Value, Total	32,171	37,172
Commercial mortgage backed securities of U.S. Government Sponsored Entities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held for Investment, Amortized Cost, Total	17,399
Held for Investment, Fair Value, Total	17,759	17,534
Available for Sale, Amortized Cost, Total	22,328
Available for Sale, Fair Value, Total	$ 22,676	$ 22,545