Business Segments and Geographic Information - Schedule of Information on Company's Business Segments (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Segment Reporting Information [Line Items]
Revenues	$ 865,400,000	$ 807,200,000	$ 1,679,700,000	$ 1,607,700,000
Adjusted segment cost of sales	(473,200,000)	(440,400,000)	(918,600,000)	(883,500,000)
Adjusted segment cost of sales	(473,200,000)	(440,400,000)	(918,600,000)	(881,000,000.0)
Interest expense – net	(15,600,000)	(8,100,000)	(31,700,000)	(17,500,000)
Depreciation	(19,000,000.0)	(16,300,000)	(37,400,000)	(32,500,000)
Amortization of intangible assets	(32,000,000)	(23,900,000)	(63,500,000)	(48,500,000)
Fair value inventory step-up charges	0	0	0	(2,500,000)
Restructuring expenses and asset impairments	(700,000)	(1,300,000)	(18,200,000)	(2,400,000)
Gain on sale of business	0	4,600,000	0	4,600,000
Income before income taxes	169,900,000	179,200,000	294,400,000	333,700,000
STC,LLC
Segment Reporting Information [Line Items]
Inventory adjustment	0	0	0	2,500,000
HST
Segment Reporting Information [Line Items]
Revenues	363,900,000	303,000,000.0	704,000,000.0	612,400,000
FMT
Segment Reporting Information [Line Items]
Revenues	310,500,000	318,900,000	600,700,000	632,400,000
Income before income taxes	169,900,000	179,200,000
Fire & Safety/Diversified Products
Segment Reporting Information [Line Items]
Revenues	191,000,000.0	185,300,000	375,000,000.0	362,900,000
Eliminations
Segment Reporting Information [Line Items]
Revenues	(2,300,000)	(1,400,000)	(4,300,000)	(2,700,000)
Adjusted segment cost of sales	2,300,000	1,400,000	4,300,000	2,700,000
Eliminations \| HST
Segment Reporting Information [Line Items]
Revenues	(1,400,000)	(800,000)	(2,800,000)	(1,500,000)
Eliminations \| FMT
Segment Reporting Information [Line Items]
Revenues	(400,000)	(500,000)	(700,000)	(700,000)
Eliminations \| Fire & Safety/Diversified Products
Segment Reporting Information [Line Items]
Revenues	(500,000)	(100,000)	(800,000)	(500,000)
Operating segments
Segment Reporting Information [Line Items]
Revenues	867,700,000	808,600,000	1,684,000,000	1,610,400,000
Adjusted segment cost of sales	(475,500,000)	(441,800,000)	(922,900,000)	(883,700,000)
Other segment expenses	(132,100,000)	(121,100,000)	(264,100,000)	(242,800,000)
Segment Adjusted EBITDA	260,100,000	245,700,000	497,000,000.0	483,900,000
Depreciation	(18,700,000)	(16,000,000.0)	(37,000,000.0)	(32,000,000.0)
Operating segments \| HST
Segment Reporting Information [Line Items]
Revenues	365,300,000	303,800,000	706,800,000	613,900,000
Adjusted segment cost of sales	(217,000,000.0)	(177,600,000)	(418,200,000)	(361,900,000)
Other segment expenses	(53,300,000)	(42,000,000.0)	(106,200,000)	(86,400,000)
Segment Adjusted EBITDA	95,000,000.0	84,200,000	182,400,000	165,600,000
Depreciation	(11,900,000)	(9,500,000)	(23,600,000)	(18,900,000)
Amortization of intangible assets	(25,400,000)	(17,200,000)	(50,000,000.0)	(34,900,000)
Operating segments \| FMT
Segment Reporting Information [Line Items]
Revenues	310,900,000	319,400,000	601,400,000	633,100,000
Adjusted segment cost of sales	(153,000,000.0)	(163,300,000)	(299,300,000)	(323,300,000)
Other segment expenses	(49,200,000)	(48,400,000)	(98,100,000)	(96,700,000)
Segment Adjusted EBITDA	108,700,000	107,700,000	204,000,000.0	213,100,000
Depreciation	(4,400,000)	(4,300,000)	(8,800,000)	(8,600,000)
Amortization of intangible assets	(5,400,000)	(5,200,000)	(10,700,000)	(10,500,000)
Operating segments \| Fire & Safety/Diversified Products
Segment Reporting Information [Line Items]
Revenues	191,500,000	185,400,000	375,800,000	363,400,000
Adjusted segment cost of sales	(105,500,000)	(100,900,000)	(205,400,000)	(198,500,000)
Other segment expenses	(29,600,000)	(30,700,000)	(59,800,000)	(59,700,000)
Segment Adjusted EBITDA	56,400,000	53,800,000	110,600,000	105,200,000
Depreciation	(2,400,000)	(2,200,000)	(4,600,000)	(4,500,000)
Amortization of intangible assets	(1,200,000)	(1,500,000)	(2,800,000)	(3,100,000)
Corporate/other
Segment Reporting Information [Line Items]
Segment Adjusted EBITDA	(22,900,000)	(21,500,000)	(51,800,000)	(51,400,000)
Depreciation	(300,000)	(300,000)	(400,000)	(500,000)
Amortization of intangible assets	$ (32,000,000.0)	$ (23,900,000)	$ (63,500,000)	$ (48,500,000)

IDEX CORP /DE/ 10-Q