Condensed Consolidated Statement of Operations (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Revenues:
Total revenues	$ 387,629	$ 327,784	$ 757,319	$ 654,861
Cost of revenues:
Liquidity payments	206,633	195,651	430,159	389,697
Brokerage, clearing, and exchange fees	15,360	14,481	31,637	30,935
Section 31 fees	22,976	11,815	22,976	35,225
Other cost of revenues	1,547	1,175	2,841	2,458
Total cost of revenues	246,516	223,122	487,613	458,315
Revenues less cost of revenues	141,113	104,662	269,706	196,546
Operating expenses:
Compensation and benefits	40,966	40,210	85,356	77,981
Information technology and communication costs	10,202	8,851	19,685	16,399
Depreciation and amortization	8,778	6,938	16,866	13,108
Occupancy costs	2,977	3,002	6,220	5,450
Professional fees and outside services	11,448	10,095	22,855	19,352
Marketing and business development	3,176	555	4,160	1,318
Acquisition-related costs	0	2,247	0	2,901
Litigation settlement	30,000	0	30,000	0
General, administrative, and other	5,769	5,473	10,799	10,453
Total operating expenses	113,316	77,371	195,941	146,962
Operating income	27,797	27,291	73,765	49,584
Non-operating (expense) income:
Change in fair value of puttable common stock	0	(1,688)	0	(1,891)
Change in fair value of puttable warrants issued with debt	0	(1,486)	0	(917)
Interest income	5,254	1,418	9,640	2,713
Interest expense and amortization of debt issuance costs	(44)	(4,902)	(89)	(9,332)
Loss on sale of intangible assets	0	(2,054)	0	(2,054)
Unrealized loss on derivative and digital assets	(337)	(4,605)	(2,878)	(47,018)
Gain on sale of business	23	0	50,570	0
Other, net	(3,911)	10,681	(2,179)	12,360
Income before income tax provision	28,782	24,655	128,829	3,445
Income tax benefit (expense)	15,426	(1,128)	85,603	(1,338)
Net income attributable to Miami International Holdings, Inc.	$ 44,208	$ 23,527	$ 214,432	$ 2,107
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Basic (in shares)	95,305,096	64,942,755	93,559,319	64,249,928
Diluted (in shares)	110,713,513	78,458,195	109,943,953	77,952,959
Earnings Per Share Reconciliation [Abstract]
Basic (in dollars per share)	$ 0.46	$ 0.36	$ 2.29	$ 0.03
Diluted (in dollars per share)	$ 0.40	$ 0.30	$ 1.95	$ 0.03
Transaction and clearing fees
Revenues:
Total revenues	$ 331,884	$ 286,139	$ 647,294	$ 575,443
Access fees
Revenues:
Total revenues	34,941	26,106	68,298	50,189
Market data fees
Revenues:
Total revenues	12,206	10,253	25,161	19,895
Other revenue
Revenues:
Total revenues	$ 8,598	$ 5,286	$ 16,566	$ 9,334