PORTFOLIO LOANS - Schedule of Activity on the Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Activity in the allowance for loan losses
ACL beginning balance	$ 169,054	$ 195,210	$ 174,023	$ 83,404
Provision for loan losses			3,925	1,024
Day 1 PCD				100,783
Day 2 Provision for loan losses	1,532	1,005	5,247	51,293
Charged-off	(9,467)	(13,383)	(17,307)	(45,218)
Recoveries	3,085	502	3,563	908
ACL ending balance	164,204	183,334	164,204	183,334
CrossFirst
Activity in the allowance for loan losses
Day 2 Provision for loan losses				42,433
Charged-off				(31,100)
Commercial loans \| C&I and other commercial
Activity in the allowance for loan losses
ACL beginning balance	57,804	89,304	61,370	21,589
Provision for loan losses			10,328	(18,240)
Day 1 PCD				75,569
Day 2 Provision for loan losses	6,772	(18,863)
Charged-off	(8,688)	(2,080)	(16,193)	(33,301)
Recoveries	1,531	217	1,914	313
ACL ending balance	57,419	68,578	57,419	68,578
Commercial loans \| C&I and other commercial \| CrossFirst
Activity in the allowance for loan losses
Day 2 Provision for loan losses				22,648
Commercial loans \| CRE and Retail real estate
Activity in the allowance for loan losses
ACL beginning balance	70,100	68,478	70,328	32,301
Provision for loan losses			(8,294)	12,977
Day 1 PCD				21,588
Day 2 Provision for loan losses	(8,060)	13,370
Charged-off	(228)	(10,916)	(228)	(11,169)
Recoveries	1,371	3	1,377	134
ACL ending balance	63,183	70,935	63,183	70,935
Commercial loans \| CRE and Retail real estate \| CrossFirst
Activity in the allowance for loan losses
Day 2 Provision for loan losses				15,104
Commercial loans \| Real estate construction
Activity in the allowance for loan losses
ACL beginning balance	12,588	8,689	11,568	3,345
Provision for loan losses			3,386	4,611
Day 1 PCD				2,112
Day 2 Provision for loan losses	2,367	4,300
Charged-off	(101)	0	(101)	0
Recoveries	1	83	2	93
ACL ending balance	14,855	13,072	14,855	13,072
Commercial loans \| Real estate construction \| CrossFirst
Activity in the allowance for loan losses
Day 2 Provision for loan losses				2,911
Retail loans \| CRE and Retail real estate
Activity in the allowance for loan losses
ACL beginning balance	27,140	26,399	29,178	23,711
Provision for loan losses			(1,672)	2,094
Day 1 PCD				1,430
Day 2 Provision for loan losses	272	2,597
Charged-off	(283)	(119)	(434)	(119)
Recoveries	87	165	144	298
ACL ending balance	27,216	29,042	27,216	29,042
Retail loans \| CRE and Retail real estate \| CrossFirst
Activity in the allowance for loan losses
Day 2 Provision for loan losses				1,628
Retail loans \| Retail other
Activity in the allowance for loan losses
ACL beginning balance	1,422	2,340	1,579	2,458
Provision for loan losses			177	(418)
Day 1 PCD				84
Day 2 Provision for loan losses	181	(399)
Charged-off	(167)	(268)	(351)	(629)
Recoveries	95	34	126	70
ACL ending balance	$ 1,531	$ 1,707	$ 1,531	1,707
Retail loans \| Retail other \| CrossFirst
Activity in the allowance for loan losses
Day 2 Provision for loan losses				$ 142

Financing Receivable, Excluding Accrued Interest, Credit Loss Expense (Reversal), Excluding Business Acquisition

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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- Definition

Amount excluding accrued interest, of allowance for credit loss on financing receivable. Excludes net investment in lease.

+ References

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-Topic 942
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- Definition

Amount, excluding accrued interest, of increase in allowance for credit loss on financing receivable from recovery. Excludes net investment in lease.

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Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

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- Definition

Amount, excluding accrued interest, of allowance for credit loss at acquisition date of financing receivable purchased with credit deterioration. Excludes net investment in lease.

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