Basis of Presentation and Significant Accounting Policies - Additional Information (Detail) (USD $)	3 Months Ended				6 Months Ended
	Jun. 30, 2012		Jun. 30, 2011		Jun. 30, 2012		Jun. 30, 2011		Dec. 31, 2011
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Percentage of completion to recognize expected profit	70.00%				70.00%
Revenues	$ 889,248,000	[1]	$ 849,801,000	[1]	$ 1,616,926,000	[1]	$ 1,749,041,000	[1]
Cost of operations	759,704,000		703,805,000		1,357,138,000		1,451,030,000
Restricted cash and cash equivalents, aggregate amount	24,024,000				24,024,000				21,962,000
Accounts receivable - other	62,500,000				62,500,000				53,400,000
Deferred profit recognition contracts
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of projects accounted under deferred profit recognition policy					2
Atlantic
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Revenues	110,304,000		52,552,000		209,908,000		92,446,000
Atlantic | Deferred profit recognition contracts
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Revenues	13,000,000		10,500,000		23,000,000		18,400,000
Cost of operations	13,000,000		10,500,000		23,000,000		18,400,000
Charter Fleet Business
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of vessels					10
Secunda International Limited
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Number of vessels					14
Consolidated Entities
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Revenues	29,000,000				39,000,000
Cost of operations	29,000,000				39,000,000
Unconsolidated joint ventures
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Revenues	1,000,000				5,000,000
Cost of operations	$ 1,000,000				$ 5,000,000
Minimum
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Equity method of accounting investment ownership	20.00%				20.00%
Maximum
Organization, Consolidation and Presentation of Financial Statements Disclosure [Line Items]
Equity method of accounting investment ownership	50.00%				50.00%

[1] Intersegment transactions included in revenues were not significant for the periods presented.