Adjustments to additional paid in capital common stock payable for prepaid service.

No definition available.

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- Definition

Bank guarantees outstanding.

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No definition available.

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- Definition

Debt instrument covenant minimum liquidity.

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No definition available.

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- Definition

Debt instrument extended maturity month and year.

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No definition available.

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- Definition

Equity investment ownership percentage.

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No definition available.

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- Definition

Letter of credit outstanding fronting fee percentage.

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No definition available.

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- Definition

Letter of credit participation fee percentage.

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No definition available.

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- Definition

Letters of credit surety bonds and other arrangements.

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No definition available.

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- Definition

Line of credit extended maturity month and year.

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No definition available.

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- Definition

Line of credit facility cash collateral amount.

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No definition available.

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- Definition

Line of credit facility collateral amount.

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No definition available.

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- Definition

Line of credit facility maximum uncommitted outstanding amount.

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No definition available.

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- Definition

Line of credit utilization fee rate.

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No definition available.

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- Definition

Maximum permitted leverage ratio.

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- Definition

Minimum collateral coverage ratio.

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Minimum fixed charge coverage ratio.

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Number of semiannual installments of principal repayment.

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Percentage of line of credit facility limitation on trade accounts receivable and cash and cash equivalents.

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Principal amount per amortizing note.

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Purchase agreement period.

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Receivables sold.

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No definition available.

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- Definition

Restricted cash collateral letters of credit.

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No definition available.

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- Definition

Settlement shares per tangible unit.

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Stock issued during period shares tangible units.

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No definition available.

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Tangible units interest rate percentage.

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No definition available.

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Tangible units stated amount per unit.

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No definition available.

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Percentage of voting equity interests acquired at the acquisition date in the business combination.

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Amount of liabilities incurred for goods and services received that are used in an entity's business and related party payables, assumed at the acquisition date.

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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

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No definition available.

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Identification of the lender and information about a contractual promise to repay a short-term or long-term obligation, which includes borrowings under lines of credit, notes payable, commercial paper, bonds payable, debentures, and other contractual obligations for payment. This may include rationale for entering into the arrangement, significant terms of the arrangement, which may include amount, repayment terms, priority, collateral required, debt covenants, borrowing capacity, call features, participation rights, conversion provisions, sinking-fund requirements, voting rights, basis for conversion if convertible and remarketing provisions. The description may be provided for individual debt instruments, rational groupings of debt instruments, or by debt in total.

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

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Balance Type:	credit
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Description of the frequency of periodic payments (monthly, quarterly, annual).

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The average effective interest rate during the reporting period.

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

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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.

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No definition available.

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Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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No definition available.

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- Definition

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

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No definition available.

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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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The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

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No definition available.

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Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

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Description of the terms of a credit facility arrangement. Terms typically include interest rate, collateral required, guarantees required, repayment requirements, and restrictions on use of assets and activities of the entity.

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Date the credit facility terminates, in CCYY-MM-DD format.

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Maximum amount borrowed under the credit facility at any time during the period.

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No definition available.

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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.

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Description of long-term debt arrangements, which are debt arrangements that originally require full repayment more than twelve months after issuance or greater than the normal operating cycle of the company, if longer, and disclosures pertaining to the underlying arrangements, including repayment terms, conversion features, interest rates, restrictions on assets and activities, debt covenants, and other matters important to users of the financial statements. Types of long-term debt arrangements include borrowing under notes payable, bonds payable, debentures, term loans, and other contractual obligations for payment.

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The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

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No definition available.

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An amount representing an agreement for an unconditional promise by the maker to pay the Entity (holder) a definite sum of money at a future date more than one year from the balance sheet date, net of any write-downs taken for collection uncertainty on the part of the holder. Such amount may include accrued interest receivable in accordance with the terms of the debt. The debt also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. This amount does not include amounts related to receivables held-for-sale.

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The fair value of notes issued in noncash investing and financing activities.

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The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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No definition available.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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Debt - Additional Information (Detail)	1 Months Ended			3 Months Ended	9 Months Ended		12 Months Ended
Debt - Additional Information (Detail)	Jun. 30, 2017 USD ($) $ / shares shares	Feb. 28, 2017 USD ($)	Apr. 30, 2014 USD ($) $ / EquityUnits shares	Jun. 30, 2017 USD ($) $ / shares shares	Sep. 30, 2017 USD ($) Installment shares	Sep. 30, 2016 USD ($) shares	Dec. 31, 2016 USD ($) shares	Apr. 30, 2017 $ / shares shares	Dec. 31, 2010	Sep. 30, 2010
Debt Instrument [Line Items]
Unamortized debt issuance costs					$ 5,000,000		$ 14,000,000
Repayment of outstanding term loans					230,715,000	$ 93,755,000
Line of Credit facility maximum amount outstanding					$ 326,000,000
Units issued \| shares			11,500,000
Tangible units interest rate percentage			6.25%
Unit price per share \| $ / EquityUnits			25
Initial principal amount per amortizing note \| $ / EquityUnits			4.1266
Common stock issued to holders of TEU \| shares	40,800,000			40,800,000	292,502,927	249,628,949	249,690,281	40,800,000
Settlement rate per tangible equity unit \| $ / shares	$ 3.5496			$ 3.5496				$ 3.5496
Bank guarantees issued					$ 504,000,000		$ 359,000,000
Bonds issued related to JRM Mexico general agreement of indemnity					56,000,000		79,000,000
Line of Credit facility maximum uncommitted outstanding amount					300,000,000
JRM Mexico [Member]
Debt Instrument [Line Items]
Letter of credit, first lien		$ 50,000,000
Amortizing note interest rate percentage		5.75%
Percentage of ownership in the subsidiary		100.00%
Purchase agreement period		364 days
Receivables sold					2,000,000
Loan agreement for equipment financing, term		21 months
Equipment financing amount		$ 47,000,000
Borrowing outstanding					$ 16,000,000
McDermott International Management [Member]
Debt Instrument [Line Items]
Percentage of ownership in the subsidiary		100.00%
Description of loan agreement					JRM Mexico’s obligations in connection with this equipment financing are guaranteed by McDermott International Management, S. de RL., one of our 100% owned subsidiaries
Financial Letters of Credit [Member]
Debt Instrument [Line Items]
Line of Credit facility maximum amount outstanding					$ 19,000,000
London Interbank Offered Rate (LIBOR) [Member] \| JRM Mexico [Member]
Debt Instrument [Line Items]
Base rate and applicable margin		4.25%
Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument maturity date					May 01, 2021
Issue of second-lien seven-year senior secured notes			$ 500,000,000
Debt instrument interest rate					8.00%
Issuance of tangible equity units					$ 240,000,000
Letter of Credit Facility [Member]
Debt Instrument [Line Items]
Cash collateralize letter of credit permitted to deposit, amount					300,000,000
Cash collateralized letters of credit					175,000,000
Letter of credit supported by cash collateral					18,000,000		16,000,000
Letter of credit supported by cash collateral maximum amount					166,000,000
Revolving Loans [Member]
Debt Instrument [Line Items]
Line of Credit facility maximum amount outstanding					$ 0
Prior Credit Agreement [Member]
Debt Instrument [Line Items]
Line of Credit facility maximum amount outstanding							$ 442,000,000
North Ocean 105 [Member]
Debt Instrument [Line Items]
Percentage of interest acquired in subsidiary									75.00%
Ownership percentage in Oceanteam ASA's	25.00%			25.00%
Amended and Restated Credit Agreement [Member]
Debt Instrument [Line Items]
Unamortized debt issuance costs	$ 21,000,000			$ 21,000,000
Repayment of outstanding term loans	217,000,000
Line of Credit facility maximum borrowing capacity	$ 1,000,000,000			$ 1,000,000,000
Commitment fee on the unused portion of credit agreement	0.50%
Letter of credit outstanding fronting fee percentage	0.25%			0.25%
Minimum fixed charge coverage ratio					1.15%
Debt instrument covenant minimum liquidity					$ 100,000,000
Minimum collateral coverage ratio					1.20%
Amended and Restated Credit Agreement [Member] \| Fiscal Quarter Ending on or Before December 31, 2019 [Member]
Debt Instrument [Line Items]
Maximum permitted leverage ratio					3.50%
Amended and Restated Credit Agreement [Member] \| Fiscal Quarter Ending After December 31, 2019 [Member]
Debt Instrument [Line Items]
Maximum permitted leverage ratio					3.25%
Amended and Restated Credit Agreement [Member] \| Financial Letters of Credit [Member]
Debt Instrument [Line Items]
Letter of credit fees					4.00%
Amended and Restated Credit Agreement [Member] \| Financial Letters of Credit [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Letter of credit participation fee percentage	3.75%			3.75%
Amended and Restated Credit Agreement [Member] \| Financial Letters of Credit [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Letter of credit participation fee percentage	4.25%			4.25%
Amended and Restated Credit Agreement [Member] \| Performance Stand By Letters Of Credit [Member]
Debt Instrument [Line Items]
Letter of credit fees					2.00%
Amended and Restated Credit Agreement [Member] \| Performance Stand By Letters Of Credit [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Letter of credit participation fee percentage	1.875%			1.875%
Amended and Restated Credit Agreement [Member] \| Performance Stand By Letters Of Credit [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Letter of credit participation fee percentage	2.125%			2.125%
Amended and Restated Credit Agreement [Member] \| Eurodollar Rate [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Base rate and applicable margin	3.75%
Amended and Restated Credit Agreement [Member] \| Eurodollar Rate [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Base rate and applicable margin	4.25%
Amended and Restated Credit Agreement [Member] \| Federal Funds Rate [Member]
Debt Instrument [Line Items]
Base rate and applicable margin	0.50%
Amended and Restated Credit Agreement [Member] \| 30-day Eurodollar Rate [Member]
Debt Instrument [Line Items]
Base rate and applicable margin	1.00%
Amended and Restated Credit Agreement [Member] \| Base Rate [Member] \| Minimum [Member]
Debt Instrument [Line Items]
Base rate and applicable margin	2.75%
Amended and Restated Credit Agreement [Member] \| Base Rate [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Base rate and applicable margin	3.25%
Amended and Restated Credit Agreement [Member] \| Second-lien Notes [Member]
Debt Instrument [Line Items]
Debt instrument face amount	$ 500,000,000			$ 500,000,000
Debt instrument, description					Our $500 million second-lien notes due in April 2021, in which case the Credit Agreement will mature on December 1, 2020.
Debt instrument extended maturity month and year	2021-04
Debt instrument maturity date	Dec. 01, 2020
Amended and Restated Credit Agreement [Member] \| Letter of Credit Facility [Member]
Debt Instrument [Line Items]
Letter of credit, first lien	$ 810,000,000			810,000,000
Amended and Restated Credit Agreement [Member] \| Revolving Loans [Member]
Debt Instrument [Line Items]
Letter of credit, first lien	300,000,000			300,000,000
Line of Credit facility maximum borrowing capacity	$ 300,000,000			$ 300,000,000
Amended and Restated Credit Agreement [Member] \| Revolving Loans [Member] \| Maximum [Member]
Debt Instrument [Line Items]
Percentage of line of credit facility limitation on trade accounts receivable and cash and cash equivalents					75.00%
Amended and Restated Credit Agreement [Member] \| Revolving Loans [Member] \| Eurodollar Rate [Member]
Debt Instrument [Line Items]
Base rate and applicable margin					4.00%
Amended and Restated Credit Agreement [Member] \| Revolving Loans [Member] \| Base Rate [Member]
Debt Instrument [Line Items]
Base rate and applicable margin					3.00%
Amended and Restated Credit Agreement [Member] \| Senior Secured Credit Facility [Member]
Debt Instrument [Line Items]
Line of credit facility, description					The senior secured credit facility established by the Credit Agreement is scheduled to mature in June 2022, unless we do not repay in full, by December 1, 2020
Line of credit, extended maturity month and year	2022-06
Line of credit, expiration date	Dec. 01, 2020
North Ocean Construction Financing [Member] \| North Ocean 105 [Member] \| Secured Debt [Member]
Debt Instrument [Line Items]
Percentage of interest acquired in subsidiary										75.00%
Number of semiannual installments of principal repayment \| Installment					17
Principal repayment, description					The financing agreement requires principal repayment in 17 consecutive semiannual installments, which commenced on October 1, 2012.
Ownership percentage in Oceanteam ASA's	25.00%			25.00%
Purchase of vessel, cash consideration				$ 11,000,000
Note payable assumed	$ 5,000,000			$ 5,000,000
Senior Amortizing Note Due April 1, 2017
Debt Instrument [Line Items]
Debt instrument maturity date			Apr. 01, 2017
Amortizing note interest rate percentage			7.75%
Middle Eastern Bank [Member] \| Letter of Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit facility maximum amount outstanding					$ 625,000,000