SECURITIES (Schedule of Securities) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Amortized Cost	$ 27,203	$ 27,203
Fair Value	26,981	24,980
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	3,653,160	2,256,189
Gross Unrealized Gains	36,927	68,543
Gross Unrealized Losses	(51,094)	(2,139)
Allowance for Credit Losses	0	0
Securities—available-for-sale	3,638,993	2,322,593
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost	521,355	421,807
Gross Unrealized Gains	21,917	26,980
Gross Unrealized Losses	(1,419)	(106)
Debt Securities, Held-to-maturity, Fair Value	541,853	448,681
Allowance for Credit Losses	(433)	(94)	$ 0
debt securities, held-to-maturity, accrued interest receivable	3,300	3,000
Debt Securities, Available-for-Sale, Accrued Interest Receivable	10,100	6,900
U.S. Government and agency obligations
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	201,101	141,668
Gross Unrealized Gains	852	1,002
Gross Unrealized Losses	(621)	(935)
Allowance for Credit Losses	0	0
Securities—available-for-sale	201,332	141,735
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost	316	340
Gross Unrealized Gains	3	7
Gross Unrealized Losses	0	0
Debt Securities, Held-to-maturity, Fair Value	319	347
Allowance for Credit Losses	0	0	0
Municipal bonds
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	293,761	283,997
Gross Unrealized Gains	15,171	19,523
Gross Unrealized Losses	(320)	(2)
Allowance for Credit Losses	0	0
Securities—available-for-sale	308,612	303,518
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost	420,555	370,998
Gross Unrealized Gains	20,743	24,130
Gross Unrealized Losses	(1,393)	(94)
Debt Securities, Held-to-maturity, Fair Value	439,905	395,034
Allowance for Credit Losses	(203)	(59)	0
Corporate bonds
Debt Securities, Trading, and Equity Securities, FV-NI [Abstract]
Amortized Cost	27,203	27,203
Fair Value	26,981	24,980
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	114,427	219,086
Gross Unrealized Gains	3,103	2,762
Gross Unrealized Losses	(183)	(79)
Allowance for Credit Losses	0	0
Securities—available-for-sale	117,347	221,769
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost	3,092	3,222
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(3)	(12)
Debt Securities, Held-to-maturity, Fair Value	3,089	3,210
Allowance for Credit Losses	(230)	(35)	0
Mortgage-backed or related securities
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	2,837,480	1,602,033
Gross Unrealized Gains	17,749	45,179
Gross Unrealized Losses	(49,961)	(1,060)
Allowance for Credit Losses	0	0
Securities—available-for-sale	2,805,268	1,646,152
Debt Securities, Held-to-Maturity, Fair Value to Amortized Cost, after Allowance for Credit Loss [Abstract]
Amortized Cost	97,392	47,247
Gross Unrealized Gains	1,171	2,843
Gross Unrealized Losses	(23)	0
Debt Securities, Held-to-maturity, Fair Value	98,540	50,090
Allowance for Credit Losses	0	0	$ 0
Asset-backed securities
Debt Securities, Available-for-sale [Abstract]
Amortized Cost	206,391	9,405
Gross Unrealized Gains	52	77
Gross Unrealized Losses	(9)	(63)
Allowance for Credit Losses	0	0
Securities—available-for-sale	$ 206,434	$ 9,419