SEGMENT REPORTING - Schedule of Segment Reporting, by Reportable Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Interest income	$ 321,952	$ 202,568	$ 617,668	$ 385,942
Interest expense	112,412	11,204	196,476	22,034
Net interest income	209,540	191,364	421,192	363,908
Provision for credit losses	45,516	14,924	95,245	21,155
Noninterest income	67,349	83,841	123,399	170,752
Noninterest expense
Salaries and employee benefits	81,336	81,545	162,246	165,826
Occupancy and equipment	12,522	12,746	25,508	25,473
Data processing and communications expenses	13,451	12,155	26,485	24,727
Other expenses	41,094	35,750	73,585	69,990
Total noninterest expense	148,403	142,196	287,824	286,016
Income before income tax expense	82,970	118,085	161,522	227,489
Income tax expense	20,335	28,019	38,466	55,725
Net income	62,635	90,066	123,056	171,764
Total assets	25,800,618	23,687,470	25,800,618	23,687,470	$ 25,053,286
Goodwill	1,015,646	1,023,056	1,015,646	1,023,056	1,015,646
Other intangible assets, net	96,800	115,613	96,800	115,613	106,194
Banking Division
Segment Reporting Information [Line Items]
Interest income	225,284	141,844	433,499	271,134
Interest expense	53,843	(10,278)	86,730	(14,733)
Net interest income	171,441	152,122	346,769	285,867
Provision for credit losses	40,831	10,175	87,971	15,401
Noninterest income	24,652	23,469	48,550	44,833
Noninterest expense
Salaries and employee benefits	55,196	46,733	111,638	95,928
Occupancy and equipment	11,175	11,168	22,781	22,242
Data processing and communications expenses	11,898	10,863	23,695	22,093
Other expenses	27,643	21,123	46,666	41,168
Total noninterest expense	105,912	89,887	204,780	181,431
Income before income tax expense	49,350	75,529	102,568	133,868
Income tax expense	13,312	19,120	26,160	36,116
Net income	36,038	56,409	76,408	97,752
Total assets	18,274,738	17,009,855	18,274,738	17,009,855
Goodwill	951,148	958,558	951,148	958,558	951,100
Other intangible assets, net	89,335	105,198	89,335	105,198
Retail Mortgage Division
Segment Reporting Information [Line Items]
Interest income	52,867	38,055	101,456	70,887
Interest expense	31,450	17,276	60,012	30,813
Net interest income	21,417	20,779	41,444	40,074
Provision for credit losses	3,278	4,499	6,131	6,086
Noninterest income	39,808	57,795	70,866	119,444
Noninterest expense
Salaries and employee benefits	21,930	31,219	42,090	62,833
Occupancy and equipment	1,224	1,406	2,507	2,877
Data processing and communications expenses	1,397	1,123	2,466	2,295
Other expenses	11,859	12,812	23,606	25,457
Total noninterest expense	36,410	46,560	70,669	93,462
Income before income tax expense	21,537	27,515	35,510	59,970
Income tax expense	4,523	5,779	7,457	12,594
Net income	17,014	21,736	28,053	47,376
Total assets	4,921,354	4,418,211	4,921,354	4,418,211
Goodwill	0	0	0	0
Other intangible assets, net	0	0	0	0
Warehouse Lending Division
Segment Reporting Information [Line Items]
Interest income	18,960	8,476	35,574	15,289
Interest expense	12,794	1,776	23,708	2,142
Net interest income	6,166	6,700	11,866	13,147
Provision for credit losses	411	867	217	645
Noninterest income	1,404	1,041	1,884	2,442
Noninterest expense
Salaries and employee benefits	772	208	1,574	491
Occupancy and equipment	0	1	1	2
Data processing and communications expenses	44	48	90	95
Other expenses	223	212	425	430
Total noninterest expense	1,039	469	2,090	1,018
Income before income tax expense	6,120	6,405	11,443	13,926
Income tax expense	1,285	1,346	2,403	2,925
Net income	4,835	5,059	9,040	11,001
Total assets	1,152,690	923,829	1,152,690	923,829
Goodwill	0	0	0	0
Other intangible assets, net	0	0	0	0
SBA Division
Segment Reporting Information [Line Items]
Interest income	4,915	4,757	9,290	11,537
Interest expense	2,584	959	5,002	1,728
Net interest income	2,331	3,798	4,288	9,809
Provision for credit losses	424	(523)	320	(666)
Noninterest income	1,476	1,526	2,081	4,017
Noninterest expense
Salaries and employee benefits	1,316	1,316	2,625	2,587
Occupancy and equipment	40	81	77	180
Data processing and communications expenses	46	29	83	57
Other expenses	333	539	755	919
Total noninterest expense	1,735	1,965	3,540	3,743
Income before income tax expense	1,648	3,882	2,509	10,749
Income tax expense	346	815	527	2,257
Net income	1,302	3,067	1,982	8,492
Total assets	257,350	264,227	257,350	264,227
Goodwill	0	0	0	0
Other intangible assets, net	0	0	0	0
Premium  Finance  Division
Segment Reporting Information [Line Items]
Interest income	19,926	9,436	37,849	17,095
Interest expense	11,741	1,471	21,024	2,084
Net interest income	8,185	7,965	16,825	15,011
Provision for credit losses	572	(94)	606	(311)
Noninterest income	9	10	18	16
Noninterest expense
Salaries and employee benefits	2,122	2,069	4,319	3,987
Occupancy and equipment	83	90	142	172
Data processing and communications expenses	66	92	151	187
Other expenses	1,036	1,064	2,133	2,016
Total noninterest expense	3,307	3,315	6,745	6,362
Income before income tax expense	4,315	4,754	9,492	8,976
Income tax expense	869	959	1,919	1,833
Net income	3,446	3,795	7,573	7,143
Total assets	1,194,486	1,071,348	1,194,486	1,071,348
Goodwill	64,498	64,498	64,498	64,498	$ 64,500
Other intangible assets, net	$ 7,465	$ 10,415	$ 7,465	$ 10,415