INVESTMENT SECURITIES - Summary of Amortized Cost and Fair Value (Details) - USD ($) $ in Thousands	Sep. 30, 2022	Dec. 31, 2021
Securities held-to-maturity:
Amortized Cost	$ 328,757	$ 0
Gross Unrealized Gains	0
Gross Unrealized Losses	(65,405)
Fair Value	263,352
Securities available-for-sale:
Amortized Cost	898,375	1,304,723
Gross Unrealized Gains	16	18,324
Gross Unrealized Losses	(50,826)	(7,344)
Securities available-for-sale, at fair value	847,565	1,315,703
U.S. government agency and U.S. government sponsored enterprise residential mortgage-backed securities
Securities held-to-maturity:
Amortized Cost	153,127
Gross Unrealized Gains	0
Gross Unrealized Losses	(29,178)
Fair Value	123,949
Securities available-for-sale:
Amortized Cost	12,012	190,382
Gross Unrealized Gains	0	2,898
Gross Unrealized Losses	(1,316)	(1,311)
Securities available-for-sale, at fair value	10,696	191,969
U.S. government agency and U.S. government sponsored enterprise collateralized mortgage obligations
Securities held-to-maturity:
Amortized Cost	61,426
Gross Unrealized Gains	0
Gross Unrealized Losses	(11,950)
Fair Value	49,476
Securities available-for-sale:
Amortized Cost	151,582	242,458
Gross Unrealized Gains	0	1,171
Gross Unrealized Losses	(10,425)	(2,088)
Securities available-for-sale, at fair value	141,157	241,541
Municipal securities
Securities held-to-maturity:
Amortized Cost	114,204
Gross Unrealized Gains	0
Gross Unrealized Losses	(24,277)
Fair Value	89,927
Securities available-for-sale:
Amortized Cost		117,913
Gross Unrealized Gains		2,641
Gross Unrealized Losses		(1,539)
Securities available-for-sale, at fair value		119,015
SBA loan pool securities
Securities available-for-sale:
Amortized Cost	12,156	14,679
Gross Unrealized Gains	4	0
Gross Unrealized Losses	(54)	(88)
Securities available-for-sale, at fair value	12,106	14,591
Non-agency residential mortgage-backed securities
Securities available-for-sale:
Amortized Cost	52,076	56,014
Gross Unrealized Gains	0	11
Gross Unrealized Losses	(10,562)	0
Securities available-for-sale, at fair value	41,514	56,025
Collateralized loan obligations
Securities available-for-sale:
Amortized Cost	492,775	521,275
Gross Unrealized Gains	0	0
Gross Unrealized Losses	(20,099)	(2,311)
Securities available-for-sale, at fair value	472,676	518,964
Corporate debt securities
Securities available-for-sale:
Amortized Cost	177,774	162,002
Gross Unrealized Gains	12	11,603
Gross Unrealized Losses	(8,370)	(7)
Securities available-for-sale, at fair value	$ 169,416	$ 173,598

Amount, before tax, of unrealized gain in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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Amount, before tax, of unrealized loss in accumulated other comprehensive income (AOCI) on investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

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