Segment Reporting - Information about Operations in Different Segments (Detail) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Segment Reporting Information [Line Items]
Revenues	$ 550,463,000us-gaap_Revenues	$ 603,811,000us-gaap_Revenues
Operating income (loss)	6,565,000us-gaap_OperatingIncomeLoss	(38,209,000)us-gaap_OperatingIncomeLoss
Capital expenditures	23,972,000	37,893,000
Depreciation and amortization	25,327,000us-gaap_DepreciationAndAmortization	24,602,000us-gaap_DepreciationAndAmortization
Drydock amortization	5,272,000us-gaap_AdjustmentForAmortization	6,946,000us-gaap_AdjustmentForAmortization
AEA [Member]
Segment Reporting Information [Line Items]
Revenues	143,313,000	181,686,000
Operating income (loss)	15,071,000	(36,412,000)
Capital expenditures	2,913,000	7,409,000
Depreciation and amortization	12,823,000	10,827,000
Drydock amortization	3,083,000	4,562,000
MEA [Member]
Segment Reporting Information [Line Items]
Revenues	153,800,000	260,300,000
Operating income (loss)	5,177,000	(2,734,000)
Capital expenditures	10,114,000	22,575,000
Depreciation and amortization	5,738,000	8,169,000
Drydock amortization	613,000	429,000
ASA [Member]
Segment Reporting Information [Line Items]
Revenues	253,350,000	161,825,000
Operating income (loss)	(12,916,000)	3,431,000
Capital expenditures	10,824,000	4,068,000
Depreciation and amortization	3,916,000	3,908,000
Drydock amortization	1,576,000	1,955,000
Corporate and Other [Member]
Segment Reporting Information [Line Items]
Operating income (loss)	(767,000)	(2,494,000)
Capital expenditures	121,000	3,841,000
Depreciation and amortization	$ 2,850,000	$ 1,698,000

The aggregate amount of recurring noncash expense charged against earnings in the period to allocate the cost of assets over their estimated remaining economic lives.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585

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- Definition

The current period expense charged against earnings on long-lived, physical assets not used in production, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset over the benefit period of such asset; or to reflect consumption during the period of an asset that is not used in production.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

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- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

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- Definition

The cash outflow associated with the acquisition of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale; includes cash outflows to pay for construction of self-constructed assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

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- Definition

Amount of revenue recognized from goods sold, services rendered, insurance premiums, or other activities that constitute an earning process. Includes, but is not limited to, investment and interest income before deduction of interest expense when recognized as a component of revenue, and sales and trading gain (loss).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.1)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 1

-Article 5

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