CONDENSED CONSOLIDATED STATEMENTS OF INCOME (UNAUDITED) - USD ($)	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Net income (loss) attributable to HMH Holding B.V. per ordinary share:
Basic (in dollars per share)	$ 17,240	$ 30,560
Diluted (in dollars per share)	$ 17,240	$ 30,560
Weighted Average number of HMH Holding B.V. ordinary shares outstanding:
Basic (in shares)	200	200
Diluted (in shares)	200	200
HMH Holding B.V. And Subsidiaries
Revenue
Revenue	$ 171,321,000	$ 198,430,000
Operating expenses
Total cost of sales	116,633,000	141,883,000
Selling, general and administrative expenses	35,111,000	36,238,000
Research and development expenses	414,000	1,031,000
Restructuring and other expenses (income), net	0	3,271,000
Total operating expenses	152,158,000	182,423,000
Operating income (loss)	19,163,000	16,007,000
Foreign currency gain (loss), net	(2,228,000)	3,993,000
Other non-operating income (loss), net	(255,000)	313,000
Interest income (expense), net	(6,953,000)	(9,179,000)
Income (loss) before income taxes	9,727,000	11,134,000
Income tax (expense) benefit	(5,852,000)	(5,256,000)
Net income (loss)	3,875,000	5,878,000
Less: Net income (loss) attributable to non-controlling interests	427,000	(234,000)
Net income (loss) attributable to HMH Holding B.V.	$ 3,448,000	$ 6,112,000
Net income (loss) attributable to HMH Holding B.V. per ordinary share:
Basic (in dollars per share)	$ 17,240	$ 30,560
Diluted (in dollars per share)	$ 17,240	$ 30,560
Weighted Average number of HMH Holding B.V. ordinary shares outstanding:
Basic (in shares)	200	200
Diluted (in shares)	200	200
Related Party | HMH Holding B.V. And Subsidiaries
Revenue
Revenue	$ 327,000	$ 90,000
Operating expenses
Interest income (expense), net	(2,658,000)	(2,440,000)
Service | HMH Holding B.V. And Subsidiaries
Revenue
Revenue	72,009,000	83,508,000
Operating expenses
Total cost of sales	53,058,000	57,078,000
Service | Nonrelated Party | HMH Holding B.V. And Subsidiaries
Revenue
Revenue	72,009,000	83,508,000
Product | HMH Holding B.V. And Subsidiaries
Operating expenses
Total cost of sales	25,367,000	46,697,000
Product | Nonrelated Party | HMH Holding B.V. And Subsidiaries
Revenue
Revenue	32,466,000	54,658,000
Spare Parts | HMH Holding B.V. And Subsidiaries
Revenue
Revenue	66,519,000	60,174,000
Operating expenses
Total cost of sales	38,208,000	38,108,000
Spare Parts | Nonrelated Party | HMH Holding B.V. And Subsidiaries
Revenue
Revenue	$ 66,519,000	$ 60,174,000