Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Contract revenues	$ 166,532	$ 154,959	$ 321,439	$ 310,297
Operating income (loss)	12,526	8,657	19,312	24,268
Foreign [Member]
Contract revenues	20,848	16,065	38,873	37,936
Dredging [Member]
Contract revenues	134,772	125,085	257,133	261,682
Operating income (loss)	12,974	13,594	17,873	31,415
Segment reporting information, intersegment revenue	62		1,374
Demolition [Member]
Contract revenues	31,760	29,874	64,306	48,615
Operating income (loss)	(448)	(4,937)	1,439	(7,147)
Segment reporting information, intersegment revenue	$ 75		$ 75

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

No definition available.

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- Definition

Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains.

+ 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=6880815&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

+ Details

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- Definition

Amount of revenue from transactions with other operating segments of the same entity.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 131

-Paragraph 27

-Subparagraph b

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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