Joint Ventures (Details) (USD $)	12 Months Ended			1 Months Ended		1 Months Ended	12 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2006 CTQ Engineering LLC firm	Dec. 31, 2012 CTQ Engineering LLC	Dec. 31, 2010 CDI Gulf International	Dec. 31, 2010 CDI Gulf International	Jun. 30, 2008 CDI Gulf International	Dec. 31, 2012 Subsidiaries	Dec. 31, 2011 Subsidiaries	Dec. 31, 2010 Subsidiaries	Jun. 30, 2008 Subsidiaries CDI Gulf International
Schedule of Equity Method Investments [Line Items]
Percentage of ownership in investment					50.00%			49.00%	67.00%
Aggregate cost of investment									$ 600,000			$ 4,100,000
Income before income taxes	32,015,000	20,130,000	(3,146,000)						1,200,000	700,000	400,000
Number of firms that make up LLC				2
Equity in losses of affiliated companies	0	0	2,299,000				1,300,000
Equity method investment write-off						$ 1,000,000