Face (par) amount of the original debt instrument that was repurchased.

No definition available.

Name:	osis_DebtInstrumentRepurchasedAndCancelledFaceAmount
Namespace Prefix:	osis_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount of debt component of the debt issuance costs.

+ References

No definition available.

+ Details

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Namespace Prefix:	osis_
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Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount of equity component of the debt issuance costs.

+ References

No definition available.

+ Details

Name:	osis_DebtIssuanceCostsEquityComponent
Namespace Prefix:	osis_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The available increase in borrowing capacity of the debt instrument under certain circumstances.

+ References

No definition available.

+ Details

Name:	osis_LineOfCreditFacilityBorrowingCapacityAvailableIncrease
Namespace Prefix:	osis_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

This element represents for line of credit facility term loan borrowing capacity.

+ References

No definition available.

+ Details

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Namespace Prefix:	osis_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of amortization expense attributable to debt issuance costs.

+ References

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate1
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Face (par) amount of debt instrument at time of issuance.

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

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Namespace Prefix:	us-gaap_
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Balance Type:	debit
Period Type:	instant

- Definition

Amount of the cost of borrowed funds accounted for as interest expense for debt.

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Balance Type:	debit
Period Type:	duration

- Definition

Represents the portion of interest incurred in the period on debt arrangements that was charged against earnings, excluding amortization of debt discount (premium) and financing costs.

+ References

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

+ References

No definition available.

+ Details

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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+ Details

Name:	us-gaap_LineOfCredit
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of borrowing capacity currently available under the credit facility (current borrowing capacity less the amount of borrowings outstanding).

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

The fee, expressed as a percentage of the line of credit facility, for available but unused credit capacity under the credit facility.

+ References

No definition available.

+ Details

Name:	us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=osis_LettersOfCreditSubFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=osis_ConvertibleSeniorNotesDue2022Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_LineOfCreditMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=osis_TermLoanMember
Namespace Prefix:
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Period Type:

Borrowings (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
Borrowings (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Sep. 30, 2022	Sep. 30, 2021	Jun. 30, 2022	Sep. 01, 2021	Feb. 28, 2017
Borrowings
Borrowings outstanding		$ 215,000		$ 60,000
Revolving credit facility
Borrowings
Maximum borrowing capacity	$ 600,000
Credit facility under term loan	150,000
Unused commitment fee (as a percent)		0.10%
Borrowings outstanding		$ 215,000
Available credit facility		$ 317,800
Revolving credit facility \| Minimum
Borrowings
Maximum borrowing capacity	535,000
Unused commitment fee (as a percent)		0.10%
Revolving credit facility \| Maximum
Borrowings
Maximum borrowing capacity	750,000
Increase in the credit agreement's borrowing capacity available under certain circumstances	250,000
Unused commitment fee (as a percent)		0.25%
Revolving credit facility \| LIBOR
Borrowings
Interest rate margin (as a percent)		1.00%
Revolving credit facility \| LIBOR \| Minimum
Borrowings
Interest rate margin (as a percent)		1.00%
Revolving credit facility \| LIBOR \| Maximum
Borrowings
Interest rate margin (as a percent)		1.75%
Letters of credit sub facility
Borrowings
Maximum borrowing capacity	$ 300,000
Amount outstanding under letters of credit		$ 67,200
1.25% Convertible Senior Notes Due 2022
Borrowings
Principal amount						$ 287,500
Interest rate (as a percentage)		1.25%
Debt issuance costs		$ 7,700
Debt component of debt issuance costs		6,500
Equity component of debt issuance costs		1,200
Total interest expense		700	$ 1,200
Contractual interest expense		500	900
Amortization of debt issuance costs		200	$ 300
Principal value of notes repurchased and cancelled					$ 242,300
Bank lines-of-credit
Borrowings
Amount outstanding under letters of credit		58,800
Available credit facility		5,900
Term Loan
Borrowings
Borrowings outstanding		$ 150,000