OPERATING SEGMENTS AND RELATED INFORMATION - Schedule of Financial Results by Operating Segment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Segment Reporting Information [Line Items]
Interest income	$ 893,860	$ 523,681	$ 480,543
Intersegment interest income	0	0	0
Interest expense	324,251	201,070	159,922
Intersegment interest expense	0	0	0
Net interest income	569,609	322,611	320,621
Provision for credit losses	52,743	7,495	2,860
Net interest income after provision for credit losses	516,866	315,116	317,761
Noninterest income
All other noninterest income	18,898	22,828	12,839
Intersegment noninterest income	0	0	0
Total noninterest income	149,975	139,682	121,214
Revenue	719,584	462,293	441,835
Noninterest expense
Salaries, wages, and employee benefits	289,063	175,619	162,597
Data processing	43,181	27,124	23,708
Amortization of intangible assets	16,614	10,057	10,432
Interchange expense	5,194	6,001	6,864
Other noninterest expense	126,149	82,693	81,470
Intersegment noninterest expense	0	0	0
Total noninterest expense	480,201	301,494	285,071
Income (loss) before income taxes	186,640	153,304	153,904
Income taxes	51,378	39,613	31,339
Net income	135,262	113,691	122,565
Wealth management fees
Noninterest income
Noninterest income	69,426	63,630	57,309
Payment technology solutions
Noninterest income
Noninterest income	20,000	21,983	21,192
Treasury management services
Noninterest income
Noninterest income	17,322	8,377	7,435
Card services and ATM fees
Noninterest income
Noninterest income	18,048	13,424	12,305
Other service charges on deposit accounts
Noninterest income
Noninterest income	6,281	9,440	10,134
Other
Segment Reporting Information [Line Items]
Interest income	6	33	105
Intersegment interest income	(62)	(372)	(54)
Interest expense	14,193	17,944	19,005
Intersegment interest expense	(3,210)	(2,664)	(3,006)
Net interest income	(11,039)	(15,619)	(15,948)
Provision for credit losses	0	0	0
Net interest income after provision for credit losses	(11,039)	(15,619)	(15,948)
Noninterest income
All other noninterest income	6,454	942	(2,182)
Intersegment noninterest income	(3,383)	(2,473)	(2,703)
Total noninterest income	3,071	(1,531)	(4,885)
Revenue	(7,968)	(17,150)	(20,833)
Noninterest expense
Salaries, wages, and employee benefits	42,964	21,128	17,767
Data processing	338	538	541
Amortization of intangible assets	0	0	0
Interchange expense	0	0	0
Other noninterest expense	16,269	9,593	6,015
Intersegment noninterest expense	(23,291)	(15,996)	(16,976)
Total noninterest expense	36,280	15,263	7,347
Income (loss) before income taxes	(44,248)	(32,413)	(28,180)
Income taxes	(6,748)	(7,478)	(7,258)
Net income	(37,500)	(24,935)	(20,922)
Other | Wealth management fees
Noninterest income
Noninterest income	0	0	0
Other | Payment technology solutions
Noninterest income
Noninterest income	0	0	0
Other | Treasury management services
Noninterest income
Noninterest income	0	0	0
Other | Card services and ATM fees
Noninterest income
Noninterest income	0	0	0
Other | Other service charges on deposit accounts
Noninterest income
Noninterest income	0	0	0
Banking | Operating Segments
Segment Reporting Information [Line Items]
Interest income	893,854	523,648	480,438
Intersegment interest income	0	324	0
Interest expense	310,058	183,126	140,917
Intersegment interest expense	3,210	2,664	3,006
Net interest income	580,586	338,182	336,515
Provision for credit losses	52,743	7,495	2,860
Net interest income after provision for credit losses	527,843	330,687	333,655
Noninterest income
All other noninterest income	11,701	20,563	14,507
Intersegment noninterest income	1,795	1,402	1,149
Total noninterest income	55,147	53,206	45,530
Revenue	635,733	391,388	382,045
Noninterest expense
Salaries, wages, and employee benefits	206,640	117,730	111,834
Data processing	36,551	20,631	18,217
Amortization of intangible assets	15,735	8,916	8,963
Interchange expense	0	0	0
Other noninterest expense	104,371	67,528	70,798
Intersegment noninterest expense	18,427	11,457	13,178
Total noninterest expense	381,724	226,262	222,990
Income (loss) before income taxes	201,266	157,631	156,195
Income taxes	50,924	40,365	32,342
Net income	150,342	117,266	123,853
Banking | Operating Segments | Wealth management fees
Noninterest income
Noninterest income	0	0	0
Banking | Operating Segments | Payment technology solutions
Noninterest income
Noninterest income	0	0	0
Banking | Operating Segments | Treasury management services
Noninterest income
Noninterest income	17,322	8,377	7,435
Banking | Operating Segments | Card services and ATM fees
Noninterest income
Noninterest income	18,048	13,424	12,305
Banking | Operating Segments | Other service charges on deposit accounts
Noninterest income
Noninterest income	6,281	9,440	10,134
Wealth Management | Operating Segments
Segment Reporting Information [Line Items]
Interest income	0	0	0
Intersegment interest income	0	0	0
Interest expense	0	0	0
Intersegment interest expense	0	0	0
Net interest income	0	0	0
Provision for credit losses	0	0	0
Net interest income after provision for credit losses	0	0	0
Noninterest income
All other noninterest income	754	1,323	514
Intersegment noninterest income	0	0	0
Total noninterest income	70,180	64,953	57,823
Revenue	70,180	64,953	57,823
Noninterest expense
Salaries, wages, and employee benefits	28,870	26,631	24,474
Data processing	2,590	2,263	1,937
Amortization of intangible assets	879	1,141	1,469
Interchange expense	0	0	0
Other noninterest expense	2,691	2,836	2,503
Intersegment noninterest expense	3,330	3,096	2,698
Total noninterest expense	38,360	35,967	33,081
Income (loss) before income taxes	31,820	28,986	24,742
Income taxes	7,637	6,956	5,938
Net income	24,183	22,030	18,804
Wealth Management | Operating Segments | Wealth management fees
Noninterest income
Noninterest income	69,426	63,630	57,309
Wealth Management | Operating Segments | Payment technology solutions
Noninterest income
Noninterest income	0	0	0
Wealth Management | Operating Segments | Treasury management services
Noninterest income
Noninterest income	0	0	0
Wealth Management | Operating Segments | Card services and ATM fees
Noninterest income
Noninterest income	0	0	0
Wealth Management | Operating Segments | Other service charges on deposit accounts
Noninterest income
Noninterest income	0	0	0
FirsTech | Operating Segments
Segment Reporting Information [Line Items]
Interest income	0	0	0
Intersegment interest income	62	48	54
Interest expense	0	0	0
Intersegment interest expense	0	0	0
Net interest income	62	48	54
Provision for credit losses	0	0	0
Net interest income after provision for credit losses	62	48	54
Noninterest income
All other noninterest income	(11)	0	0
Intersegment noninterest income	1,588	1,071	1,554
Total noninterest income	21,577	23,054	22,746
Revenue	21,639	23,102	22,800
Noninterest expense
Salaries, wages, and employee benefits	10,589	10,130	8,522
Data processing	3,702	3,692	3,013
Amortization of intangible assets	0	0	0
Interchange expense	5,194	6,001	6,864
Other noninterest expense	2,818	2,736	2,154
Intersegment noninterest expense	1,534	1,443	1,100
Total noninterest expense	23,837	24,002	21,653
Income (loss) before income taxes	(2,198)	(900)	1,147
Income taxes	(435)	(230)	317
Net income	(1,763)	(670)	830
FirsTech | Operating Segments | Wealth management fees
Noninterest income
Noninterest income	0	0	0
FirsTech | Operating Segments | Payment technology solutions
Noninterest income
Noninterest income	20,000	21,983	21,192
FirsTech | Operating Segments | Treasury management services
Noninterest income
Noninterest income	0	0	0
FirsTech | Operating Segments | Card services and ATM fees
Noninterest income
Noninterest income	0	0	0
FirsTech | Operating Segments | Other service charges on deposit accounts
Noninterest income
Noninterest income	$ 0	$ 0	$ 0