Acquisition of OceanGeo - Pro Forma Income Statement Information (Details) $ / shares in Units, $ in Thousands	6 Months Ended
	Jun. 30, 2014 USD ($) $ / shares	Jun. 30, 2015 project
Business Combinations [Abstract]
Net revenues	$ 275,362
Income from operations	26,712
Net income	79,631
Net income attributable to ION	$ 77,866
Basic and diluted net income per common share, in dollars per share | $ / shares	$ 0.47
Number of projects in negotiation | project		2