Debt - Narrative (Details) - USD ($) $ in Thousands	4 Months Ended	8 Months Ended	12 Months Ended
Debt - Narrative (Details) - USD ($) $ in Thousands	Sep. 30, 2024	May 31, 2024	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023	Dec. 07, 2023	Dec. 22, 2021
Line of Credit Facility [Line Items]
Maximum borrowing capacity							$ 215,000
Weighted average interest rate on debt			6.00%
Debt issuance costs						$ 9,700
Debt instrument, basis spread on variable rate	1.75%	2.25%
Proceeds from long-term debt			$ 150,000	$ 214,062	$ 0
Payment for Debt Extinguishment or Debt Prepayment Cost				18,900
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage			0.20%
Repayments of Debt			$ 114,300	$ 91,100
Line of Credit Facility, Increase (Decrease), Net			$ 150,000
Credit Agreement [Domain] \| Line of Credit
Line of Credit Facility [Line Items]
Debt Instrument, Covenant, Leverage Ratio, Minimum			3
Debt Instrument, Covenant, Liquidity Ratio, Total Net Leverage Ratio			3
Debt Instrument, Covenant, Holiday			3.5
Total Net Leverage Ratio, Unrestricted Cash, Maximum			$ 50,000
2021 Credit Agreement
Line of Credit Facility [Line Items]
Debt issuance costs						1,300
Secured Debt [Member]
Line of Credit Facility [Line Items]
Maximum borrowing capacity							350,000
Secured Debt [Member] \| Base Rate \| Federal Funds Rate
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			0.50%
Secured Debt [Member] \| Base Rate \| LIBOR
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			1.00%
Secured Debt [Member] \| Minimum \| Base Rate
Line of Credit Facility [Line Items]
Debt Instrument, Interest Rate, Basis for Effective Rate			0.00
Revolving Credit Facility
Line of Credit Facility [Line Items]
Maximum borrowing capacity						250,000	35,000
Line Of Credit Facility, Accordion Feature, Increase Limit						95,000
Revolving Credit Facility \| Minimum
Line of Credit Facility [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage			0.20%
Revolving Credit Facility \| Minimum \| Base Rate
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			0.75%
Revolving Credit Facility \| Minimum \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			1.75%
Revolving Credit Facility \| Maximum
Line of Credit Facility [Line Items]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage			0.35%
Revolving Credit Facility \| Maximum \| Base Rate
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			1.75%
Revolving Credit Facility \| Maximum \| Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate
Line of Credit Facility [Line Items]
Debt instrument, basis spread on variable rate			2.75%
Letter of Credit
Line of Credit Facility [Line Items]
Maximum borrowing capacity						$ 10,000	10,000
Swingline Subfacility
Line of Credit Facility [Line Items]
Maximum borrowing capacity							$ 10,000

DIGI INTERNATIONAL INC 10-K