Condensed Consolidated Statements of Operations - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Income Statement [Abstract]
Contract revenues	$ 86,091	$ 90,251	$ 167,546	$ 171,509
Costs of contract revenues	80,066	84,378	153,065	157,989
Gross profit	6,025	5,873	14,481	13,520
Selling, general and administrative expenses	8,794	8,129	17,486	16,093
Loss from operations	(2,769)	(2,256)	(3,005)	(2,573)
Other (expense) income
Gain from sale of assets, net	57	84	100	176
Other income	0	467	0	467
Interest income	4	0	17	10
Interest expense	(252)	(194)	(490)	(324)
Other (expense) income, net	(191)	357	(373)	329
Loss before income taxes	(2,960)	(1,899)	(3,378)	(2,244)
Income tax benefit	(1,115)	(736)	(1,276)	(871)
Net loss attributable to Orion common stockholders	$ (1,845)	$ (1,163)	$ (2,102)	$ (1,373)
Basic loss per share (in dollars per share)	$ (0.07)	$ (0.04)	$ (0.08)	$ (0.05)
Diluted loss per share (in dollars per share)	$ (0.07)	$ (0.04)	$ (0.08)	$ (0.05)
Shares used to compute loss per share
Basic (shares)	27,352,523	27,422,658	27,478,514	27,410,384
Diluted (shares)	27,352,523	27,422,658	27,478,514	27,410,384