Summary Of Major Accounting Policies - Percentage-of-Completion (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Schedule Temporary Differences Using Percentage of Completion [Line Items]
Revenue Recognition, Multiple-deliverable Arrangements, Percentage of Revenue Accounted Under the Percentage of Completion Method	15.00%
Contract in Unbilled Receivable Position [Member]
Schedule Temporary Differences Using Percentage of Completion [Line Items]
Fixed-price Contract, Percentage of Completion, Revenue Recognized to Date	$ 368,888	$ 199,654
Billed Contracts Receivable	(312,968)	(168,215)
Costs in Excess of Billings on Uncompleted Contracts or Programs	55,920	31,439
Contracts in Unearned Revenue Position [Member]
Schedule Temporary Differences Using Percentage of Completion [Line Items]
Fixed-price Contract, Percentage of Completion, Revenue Recognized to Date	(109,547)	(86,264)
Billed Contracts Receivable	196,501	200,909
Billings in Excess of Cost	$ 86,954	$ 114,645

Fixed-price Contract, Percentage of Completion, Revenue Recognized to Date

No definition available.

Name:	oii_FixedPriceContractPercentageOfCompletionRevenueRecognizedToDate
Namespace Prefix:	oii_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Revenue Recognition, Multiple-deliverable Arrangements, Percentage of Revenue Accounted Under the Percentage of Completion Method

+ References

No definition available.

+ Details

Name:	oii_RevenueRecognitionMultipleDeliverableArrangementsPercentageOfRevenueAccountedUnderPercentageOfCompletionMethod
Namespace Prefix:	oii_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	oii_ScheduleTemporaryDifferencesUsingPercentageOfCompletionLineItems
Namespace Prefix:	oii_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amounts due for billed services rendered or to be rendered, actions taken or to be taken, or a promise to refrain from taking certain actions in accordance with the terms of a legally binding agreement between the Company and, at a minimum, one other party. An example would be amounts billed to customers under contracts or programs but not paid as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3(c))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_BilledContractReceivables
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Liability attributable to (i) billings in excess of costs under the percentage of completion contract accounting method representing the difference between contractually invoiced amounts (billings) and revenue recognized based, for example, on costs incurred to estimated total costs at period end or (ii) contractually invoiced amounts (billings) in excess of costs incurred and accumulated under the completed contract accounting method.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 35

-Section 45

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6802688&loc=d3e57788-111642

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 35

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6802688&loc=d3e57807-111642

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 35

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6802688&loc=d3e57795-111642

+ Details

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

- Definition

Amount of receivable reflecting the cost incurred on uncompleted contracts in excess of related billings.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 35

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6802688&loc=d3e57807-111642

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 35

-Section 45

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6802688&loc=d3e57795-111642

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.3(c)(3))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 912

-SubTopic 310

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6471842&loc=d3e55302-109406

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 3

-Subparagraph c(2), c(3), c(4)

-Article 5

+ Details

Name:	us-gaap_CostsInExcessOfBillingsOnUncompletedContractsOrPrograms
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	oii_PercentageOfCompletionContractPositionAxis=oii_ContractInUnbilledReceivablePositionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	oii_PercentageOfCompletionContractPositionAxis=oii_ContractsInUnearnedRevenuePositionMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: