ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) - Reclassifications out of AOCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	$ 32,070	$ 25,995	$ 5,413
Reclassification out of Accumulated Other Comprehensive Income | AFS securities
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gross reclassification	(564)	0	(126)
Income tax expense	212	0	50
Reclassification, net of tax	(352)	0	(76)
Reclassification out of Accumulated Other Comprehensive Income | Cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gross reclassification	452	161	0
Income tax expense	(170)	(62)	0
Reclassification, net of tax	$ 282	$ 99	$ 0