OTHER COMPREHENSIVE INCOME - RECLASSIFICATION (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Significant amounts reclassified out of each component of AOCI
Interest expense on deposits	$ (2,324)	$ (1,347)	$ (4,203)	$ (2,739)
Interest expense on FHLB advances	(1,943)	(2,973)	(4,235)	(5,926)
Total interest expense	(4,684)	(4,563)	(9,129)	(9,144)
Income tax expense	(5,198)	(4,359)	(15,252)	(13,252)
NET INCOME	10,071	8,340	30,088	26,075
Unrealized loss on cash flow hedge | Reclassification out of Accumulated Other Comprehensive Income
Significant amounts reclassified out of each component of AOCI
Interest expense on deposits	(29)	(43)	(63)	(86)
Interest expense on FHLB advances	(29)	(43)	(61)	(87)
Total interest expense	(58)	(86)	(124)	(173)
Income tax expense	20	30	43	61
NET INCOME	$ (38)	$ (56)	$ (81)	$ (112)