Document and Entity Information (USD $)	6 Months Ended
	Jun. 30, 2011
Entity Information [Line Items]
Entity Registrant Name	ORION MARINE GROUP INC.
Entity Central Index Key	0001402829
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Document Type	10-Q
Document Period End Date	Jun. 30, 2011
Document Fiscal Year Focus	2011
Document Fiscal Period Focus	Q2
Amendment Flag	false
Entity Common Stock, Shares Outstanding	26,717,341
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float	$ 247,583,536