Condensed Consolidated Statements of Operations (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]
Contract revenues	$ 106,976	$ 88,992	$ 278,485	$ 248,131
Costs of contract revenues	94,070	83,381	252,060	228,859
Gross profit	12,906	5,611	26,425	19,272
Selling, general and administrative expenses	7,859	7,974	23,953	23,491
Income (loss) from operations	5,047	(2,363)	2,472	(4,219)
Other (expense) income
(Loss) gain from sale of assets, net	(12)	0	165	0
Other income	1	0	467	614
Interest income	0	0	12	13
Interest expense	(198)	(111)	(523)	(427)
Other (expense) income, net	(209)	(111)	121	200
Income (loss) before income taxes	4,838	(2,474)	2,593	(4,019)
Income tax expense (benefit)	1,876	(1,500)	1,006	(2,161)
Net income (loss)	2,962	(974)	1,587	(1,858)
Net loss attributable to noncontrolling interest	0	(31)	0	(56)
Net income (loss) attributable to Orion common stockholders	$ 2,962	$ (943)	$ 1,587	$ (1,802)
Basic loss per share (in dollars per share)	$ 0.11	$ (0.03)	$ 0.06	$ (0.07)
Diluted loss per share (in dollars per share)	$ 0.11	$ (0.03)	$ 0.06	$ (0.07)
Shares used to compute income (loss) per share
Basic (shares)	27,468,240	27,318,180	27,430,162	27,273,176
Diluted (shares)	27,802,734	27,318,180	27,809,208	27,273,176