Description of Share Exchange Ratio

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Dividends paid to Parent prior to spin-off.

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Number of Vessels

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Spin Off Transaction And Distribution Of Common Stock, Percentage

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Spin-off transaction and distribution of common stock shares.

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The charge against earnings in the period, comprised of costs incurred associated with an exit or disposal activity other than for a discontinued operations as defined under generally accepted accounting principles. Costs of such activities include those for one-time termination benefits, termination of an operating lease or other contract, consolidating or closing facilities, and relocating employees, and costs associated with an ongoing benefit arrangement, but excludes costs associated with the retirement of a long-lived asset.

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The loss (gain) resulting from the write-down of the carrying value of assets classified as a disposal group, but one which is not further classified as a discontinued operation, to fair value less cost to sell. A (gain) results from a subsequent increase in fair value less cost to sell, but not in excess of the cumulative loss previously recognized. For example, the write-down of a disposal group subject to a plan of sale, which was not sold in the current period, to its held-for-sale value. The loss (gain) is included in income from continuing operations before income taxes in the income statement.

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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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The value of all consideration given or received by the Entity in the significant acquisition or disposal.

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The difference between the value of the consideration received by the Entity on the sale or disposal and net book value of assets sold or disposed, before any tax related impact.

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DISCONTINUED OPERATIONS AND OTHER ITEMS - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	1 Months Ended	3 Months Ended		1 Months Ended
	Sep. 30, 2010 Charter Fleet Business Vessel	Jul. 30, 2010 The Babcock and Wilcox Company	Sep. 30, 2010 Fabrication Facility	Aug. 26, 2011 Atlantic	Aug. 26, 2011 Atlantic Discontinued Operation or Asset Disposal Vessel
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Write-down on carrying value of assets disposal of discontinued operations	$ 27.7
Outstanding common stock received In connection with the spin-off of B&W, Percentage		100.00%
Outstanding common stock received In connection with the spin-off of B&W, shares		116
B&W common stock received for every shares of common stock		In connection with the spin-off, our stockholders received 100% (approximately 116 million shares) of the outstanding common stock of B&W. The distribution of B&W common stock occurred by way of a pro rata stock dividend to our stockholders. Each stockholder generally received one share of B&W common stock for every two shares of our common stock held by such stockholder on July 9, 2010, and cash in lieu of any fractional shares. Prior to the completion of the spin-off, B&W made a cash distribution to us totaling $100 million.
Cash distribution to MII to maintain appropriate working capital and liquidity levels		100
Cash consideration received from vessel sale				8
Pre-tax gain from sale of vessel				7.7
Number of vessels	10				23
Costs to discontinue development plans for a new fabrication yard, including estimated lease termination costs			$ 20