ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 2,469,582	$ 1,456,347
Reclassification for gains included in net income, net of tax	0	(94)
Current year changes, net of tax	21,618	21,382
Ending balance	2,460,130	1,537,121
Unrealized Gain (Loss) on Derivatives
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(147)	351
Reclassification for gains included in net income, net of tax	0	0
Current year changes, net of tax	14	(412)
Ending balance	(133)	(61)
Unrealized Gain (Loss) on Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	18,142	(5,177)
Reclassification for gains included in net income, net of tax	0	(94)
Current year changes, net of tax	21,604	21,794
Ending balance	39,746	16,523
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	17,995	(4,826)
Ending balance	$ 39,613	$ 16,462