Quarterly report pursuant to Section 13 or 15(d)

Summary of Significant Accounting Policies (Details Textual)

v2.4.0.6
Summary of Significant Accounting Policies (Details Textual) (USD $)
 3 Months Ended 6 Months Ended 1 Months Ended
Jun. 30, 2012
Jun. 30, 2011
Jun. 30, 2012
Jun. 30, 2011
Mar. 31, 2012
Dec. 31, 2011
Mar. 31, 2011
Dec. 31, 2010
Apr. 30, 2012
Howard Midstream Energy Partners, LLC [Member]
Mar. 31, 2012
Howard Midstream Energy Partners, LLC [Member]
Jun. 30, 2011
Howard Midstream Energy Partners, LLC [Member]
Jun. 22, 2011
Howard Midstream Energy Partners, LLC [Member]
Summary of Significant Accounting Policies (Textual) [Abstract]                        
Acquired ownership interest in HEP                 31.00%     39.00%
Payment to acquire equity method investment $ 48,844,000 $ 35,000,000 $ 53,750,000 $ 35,000,000         $ 47,400,000 $ 4,900,000 $ 35,000,000  
Number of shares acquired in equity method investment                 45,435      
Summary of Significant Accounting Policies (Additional Textual) [Abstract]                        
Cash and cash equivalents 172,868,000 380,382,000 172,868,000 380,382,000 177,367,000 315,349,000 503,019,000 539,221,000        
Cash equivalents 71,200,000   71,200,000     165,900,000            
Cash and cash equivalents held in domestic bank accounts 28,700,000   28,700,000     230,900,000            
Cash and cash equivalents held in foreign bank accounts 144,200,000   144,200,000     84,400,000            
Total allowances for doubtful accounts 5,034,000   5,034,000     3,763,000            
Allowances on accounts receivable, current 5,034,000   5,034,000     3,763,000            
Current retainage balances 166,000,000   166,000,000     117,100,000            
Non-current retainage balances 17,300,000   17,300,000     28,300,000            
Unbilled receivables 162,500,000   162,500,000     140,800,000            
Number of days after accounts receivable are treated as delinquent     30 days                  
Number of days related to outstanding accounts receivable for analysis of the allowance for doubtful accounts     at least 90 days                  
Decrease in fair value of reporting units considered, for impairment calculation           10.00%            
Change orders and/or claims 207,100,000   207,100,000     77,300,000            
Fiber Optic Licensing Terms, Minimum in years     5 years 5 years                
Fiber Optic Licensing Terms, Maximum in years     25 years 25 years                
Fiber optic deferred revenue 46,200,000   46,200,000     47,400,000            
Fiber optic non-current deferred revenue 37,700,000   37,700,000     38,300,000            
Unrecognized tax benefits increase (decrease)     (11,900,000)                  
Unrecognized tax benefits $ 52,100,000   $ 52,100,000     $ 47,400,000