Litigation (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended
	Apr. 30, 2012	Mar. 31, 2011	Feb. 28, 2011	Sep. 30, 2010	Jan. 31, 2010	Oct. 31, 2009
Litigation (Textual) [Abstract]
Minimum distance from coast to make alleged activities not actionable under patent infringement law		more than 12 miles
Advanced to ION Sarl under the bridge loan						$ 10.0
ION Sarl repaid						10.0
Repay under Bridge loan and unspecified monetary damages						10.0
Compensatory damages awarded in connection with infringement of patent by Sercel					25.2
Disallowed the award of lost profits associated with infringing products				5.4
Disallowed the award of lost profits associated with certain infringing pre-verdict marine sales				9.0
Awarded for damages, plus interest			10.7
Payment made for litigation settlement	$ 12.0