Contracts between ARO and Saudi Aramco

No definition available.

Name:	rdc_ContractsbetweenAROandSaudiAramco
Namespace Prefix:	rdc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of drilling rigs expected to be purchase by the joint venture.

+ References

No definition available.

+ Details

Name:	rdc_NumberOfDrillingRigsToBePurchasedByJointVenture
Namespace Prefix:	rdc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of fleet of self-elevating mobile offshore jack-up drilling units.

+ References

No definition available.

+ Details

Name:	rdc_NumberOfFleetOfSelfElevatingMobileOffshoreJackUpDrillingUnits
Namespace Prefix:	rdc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of Drillships.

+ References

No definition available.

+ Details

Name:	rdc_NumberofDrillships
Namespace Prefix:	rdc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of jackups leased by ARO

+ References

No definition available.

+ Details

Name:	rdc_NumberofjackupsleasedbyARO
Namespace Prefix:	rdc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

The period of joint venture funding of the purchase of drilling rigs (in PYMD format).

+ References

No definition available.

+ Details

Name:	rdc_PeriodOfJointVentureFundingOfDrillingRigs
Namespace Prefix:	rdc_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Shares Received After Merger

+ References

No definition available.

+ Details

Name:	rdc_SharesReceivedafterMerger
Namespace Prefix:	rdc_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Value of equity interests (such as common shares, preferred shares, or partnership interest) issued or issuable to acquire the entity.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)(4)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

+ Details

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

- Definition

Number of shares of equity interests issued or issuable to acquire entity.

+ References

+ Details

Name:	us-gaap_BusinessAcquisitionEquityInterestsIssuedOrIssuableNumberOfSharesIssued
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6613-128477

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=35744584&loc=d3e6927-128479

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=109124213&loc=d3e6578-128477

+ Details

Name:	us-gaap_BusinessCombinationConsiderationTransferred1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair value at acquisition-date of the equity interest in the acquiree held by the acquirer, immediately before the acquisition date for businesses combined in stages.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (g)(1)
-URI http://asc.fasb.org/extlink&oid=79982066&loc=d3e1392-128463

+ Details

Name:	us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Face amount or stated value per share of common stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_CommonStockParOrStatedValuePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 50
-Paragraph 3
-Subparagraph (a)(1)
-URI http://asc.fasb.org/extlink&oid=114001798&loc=d3e33918-111571

+ Details

Name:	us-gaap_EquityMethodInvestmentOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfOperatingSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

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

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

Name:	us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_RevenueRecognitionMultipleDeliverableArrangementsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Price of a single share of a number of saleable stocks of a company.

+ References

No definition available.

+ Details

Name:	us-gaap_SharePrice
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	srt_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis=rdc_SaudiArabiaJointVentureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=rdc_SaudiAramcoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=rdc_EnscoMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=rdc_RowanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

Nature of Operations and Basis of Presentation (Details) $ / shares in Units, shares in Millions		3 Months Ended
	Apr. 11, 2019 USD ($) $ / shares shares	Mar. 31, 2019 USD ($) drilling_unit segment	Apr. 10, 2019 USD ($) $ / shares	Jan. 28, 2019 $ / shares	Jan. 01, 2019 USD ($)
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Operating Lease, Liability		$ 13,700,000			$ 14,500,000
Number of Operating Segments \| segment		3
Number of ultra-deepwater drillships \| drilling_unit		4
Number of fleet of self-elevating mobile offshore jack-up drilling units \| drilling_unit		21
Operating Lease, Right-of-Use Asset		$ 12,300,000			$ 13,200,000
Number of jackups leased by ARO		9
Contracts between ARO and Saudi Aramco		2
Saudi Arabia Joint Venture [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Number of fleet of self-elevating mobile offshore jack-up drilling units \| drilling_unit		7
Period Of Joint Venture Funding Of Drilling Rigs		10 years
Saudi Arabia Joint Venture [Member] \| Saudi Aramco [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Equity Method Investment, Ownership Percentage		50.00%
Parent Company [Member] \| Saudi Arabia Joint Venture [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Equity Method Investment, Ownership Percentage		50.00%
Ensco [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Common Stock, Par or Stated Value Per Share \| $ / shares				$ 0.10
Subsequent Event [Member] \| Ensco [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Shares Received by Rowan Shareholders for Rowan Ensco merge \| $ / shares	$ 2.750
Business Acquisition, Equity Interest Issued or Issuable, Number of Shares \| shares	88.3
Subsequent Event [Member] \| Rowan [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Business Combination, Consideration Transferred	$ 1,400,000,000
Business Acquisition, Equity Interest Issued or Issuable, Value Assigned			$ 43.67
Share Price \| $ / shares			$ 15.88
Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value	$ 2,600,000
Maximum [Member] \| Saudi Arabia Joint Venture [Member]
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Number Of Drilling Rigs To Be Purchased By Joint Venture \| drilling_unit		20