ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	$ 3,197,400	$ 2,966,451
Reclassification for gains included in net income, net of tax	0	0
Current year changes, net of tax	10,926	(17,431)
Balance at end of period	3,253,195	3,007,159
Unrealized Gain (Loss) on Securities
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(46,507)	15,590
Reclassification for gains included in net income, net of tax	0	0
Current year changes, net of tax	10,926	(17,431)
Balance at end of period	(35,581)	(1,841)
Accumulated Other Comprehensive Income (Loss)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Balance at beginning of period	(46,507)	15,590
Balance at end of period	$ (35,581)	$ (1,841)