SEGMENT REPORTING - Schedule of Segment Reporting, by Reportable Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Dec. 31, 2023
Segment Reporting Information [Line Items]
Interest income	$ 329,452	$ 295,716
Interest expense	128,064	84,064
Net interest income	201,388	211,652
Provision for credit losses	21,105	49,729
Noninterest income	65,878	56,050
Noninterest expense
Salaries and employee benefits	82,930	80,910
Occupancy and equipment	12,885	12,986
Data processing and communications expenses	14,654	13,034
Other expenses	38,242	32,491
Total noninterest expense	148,711	139,421
Income before income tax expense	97,450	78,552
Income tax expense	23,138	18,131
Net income	74,312	60,421
Total assets	25,655,445	26,088,384	$ 25,203,699
Goodwill	1,015,646	1,015,646	1,015,646
Other intangible assets, net	83,527	101,488	$ 87,949
Banking Division
Segment Reporting Information [Line Items]
Interest income	235,122	212,590
Interest expense	70,654	35,305
Net interest income	164,468	177,285
Provision for credit losses	19,127	47,036
Noninterest income	26,363	24,503
Noninterest expense
Salaries and employee benefits	58,916	57,751
Occupancy and equipment	11,753	11,643
Data processing and communications expenses	13,184	11,834
Other expenses	24,447	19,445
Total noninterest expense	108,300	100,673
Income before income tax expense	63,404	54,079
Income tax expense	16,028	13,029
Net income	47,376	41,050
Total assets	18,553,964	19,142,989
Goodwill	951,148	951,148
Other intangible assets, net	78,275	93,285
Retail Mortgage Division
Segment Reporting Information [Line Items]
Interest income	55,099	48,589
Interest expense	31,812	28,562
Net interest income	23,287	20,027
Provision for credit losses	2,332	2,853
Noninterest income	38,765	31,058
Noninterest expense
Salaries and employee benefits	21,073	20,160
Occupancy and equipment	1,049	1,283
Data processing and communications expenses	1,366	1,069
Other expenses	12,530	11,747
Total noninterest expense	36,018	34,259
Income before income tax expense	23,702	13,973
Income tax expense	4,978	2,934
Net income	18,724	11,039
Total assets	4,971,058	4,879,135
Goodwill	0	0
Other intangible assets, net	0	0
Warehouse Lending Division
Segment Reporting Information [Line Items]
Interest income	16,483	16,614
Interest expense	10,455	10,914
Net interest income	6,028	5,700
Provision for credit losses	145	(194)
Noninterest income	740	480
Noninterest expense
Salaries and employee benefits	888	802
Occupancy and equipment	7	1
Data processing and communications expenses	25	46
Other expenses	237	202
Total noninterest expense	1,157	1,051
Income before income tax expense	5,466	5,323
Income tax expense	1,148	1,118
Net income	4,318	4,205
Total assets	897,460	936,169
Goodwill	0	0
Other intangible assets, net	0	0
SBA Division
Noninterest expense
Net income	0	0
Premium  Finance  Division
Segment Reporting Information [Line Items]
Interest income	22,748	17,923
Interest expense	15,143	9,283
Net interest income	7,605	8,640
Provision for credit losses	(499)	34
Noninterest income	10	9
Noninterest expense
Salaries and employee benefits	2,053	2,197
Occupancy and equipment	76	59
Data processing and communications expenses	79	85
Other expenses	1,028	1,097
Total noninterest expense	3,236	3,438
Income before income tax expense	4,878	5,177
Income tax expense	984	1,050
Net income	3,894	4,127
Total assets	1,232,963	1,130,091
Goodwill	64,498	64,498
Other intangible assets, net	$ 5,252	$ 8,203