Accumulated Other Comprehensive Income - Changes in AOCI by Component (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Jun. 30, 2026	Jun. 30, 2025	Jun. 30, 2026	Jun. 30, 2025
Attributable to Matthews:
Beginning balance	$ 512,219	$ 408,240	$ 480,942	$ 437,206
OCI, net of tax	164	97,446	22,928	91,014
Ending balance	485,968	513,832	485,968	513,832
AOCI Attributable to Parent
Attributable to Matthews:
Beginning balance	(55,246)	(175,174)	(78,010)	(168,742)
OCI before reclassification	315	5,277	5,567	(6,626)
Amounts reclassified from AOCI	(151)	92,169	17,361	97,640
OCI, net of tax	164	97,446	22,928	91,014
Ending balance	(55,082)	(77,728)	(55,082)	(77,728)
Post-retirement benefit plans
Attributable to Matthews:
Beginning balance	5,945	4,533	7,540	4,955
OCI before reclassification	(27)	208	(108)	125
Amounts reclassified from AOCI	(190)	(164)	(1,704)	(503)
OCI, net of tax	(217)	44	(1,812)	(378)
Ending balance	5,728	4,577	5,728	4,577
Currency translation adjustment
Attributable to Matthews:
Beginning balance	(61,327)	(180,882)	(84,997)	(174,623)
OCI before reclassification	(648)	6,264	3,864	(6,343)
Amounts reclassified from AOCI	(17)	92,537	19,141	98,885
OCI, net of tax	(665)	98,801	23,005	92,542
Ending balance	(61,992)	(82,081)	(61,992)	(82,081)
Cash Flow Hedges
Attributable to Matthews:
Beginning balance	136	1,175	(553)	926
OCI before reclassification	990	(1,195)	1,811	(408)
Amounts reclassified from AOCI	56	(204)	(76)	(742)
OCI, net of tax	1,046	(1,399)	1,735	(1,150)
Ending balance	$ 1,182	(224)	$ 1,182	(224)
AOCI Attributable to Noncontrolling Interest
Attributable to Matthews:
Beginning balance		289		289
OCI before reclassification		0		0
OCI, net of tax		0		0
Ending balance		289		289
Post-retirement benefit plans
Attributable to Matthews:
Beginning balance		0		0
OCI before reclassification		0		0
OCI, net of tax		0		0
Ending balance		0		0
Currency translation adjustment
Attributable to Matthews:
Beginning balance		289		289
OCI before reclassification		0		0
OCI, net of tax		0		0
Ending balance		289		289
Cash Flow Hedges
Attributable to Matthews:
Beginning balance		0		0
OCI before reclassification		0		0
OCI, net of tax		0		0
Ending balance		$ 0		$ 0