Quarterly report pursuant to Section 13 or 15(d)

Debt Obligations (Details Textuals)

Debt Obligations (Details Textuals) (USD $)
In Millions, unless otherwise specified
1 Months Ended 6 Months Ended
Aug. 31, 2011
Jun. 30, 2011
Aug. 02, 2011
May 14, 2010
Debt Obligations (Textuals) [Abstract]        
Senior secured revolving credit facility   $ 475.0 $ 700.0  
Maturity date of senior secured revolving credit facility 02-08-2016 19-09-2012    
Letters of credit issued under credit facility (approximately)   187.5    
Credit facility available for revolving loans or issuing new letters of credit   287.5    
Interest Rate In excess of Eurodollar Rate minimum   0.875%    
Interest Rate In excess of Eurodollar Rate maximum   1.75%    
Interest Rate In excess of Base Rate minimum   0.00%    
Interest Rate In excess of Base Rate maximum   0.75%    
Letter of credit fee minimum   0.875%    
Letter of credit fee maximum   1.75%    
Commitment fee minimum   0.15%    
Commitment fee maximum   0.35%    
Base rate in excess of Federal Funds Rate   0.05%    
Reduction in Quanta's maximum funded debt and maximum senior debt by all cash and cash equivalents in excess of amount   25.0    
Cross default provisions with debt instruments exceeding this amount   15.0    
Letters of credit outstanding amount issued under agreements other than credit facility   7.4    
Annual interest rate of convertible subordinated notes       3.75%
Outstanding aggregate principal amount       $ 143.8
Redemption price as a percentage of the principle amount of the 3.75% convertible subordinated notes       101.607%