Quarterly report pursuant to Section 13 or 15(d)

Derivative Instruments and Hedging Activities (Details Textuals)

 v2.3.0.11
Derivative Instruments and Hedging Activities (Details Textuals) (USD $)
In Millions, unless otherwise specified
 1 Months Ended 6 Months Ended 12 Months Ended
Aug. 31, 2009
Jun. 30, 2011
Dec. 31, 2009
Dec. 31, 2010
Additional Derivative Instruments and Hedging Activities (Textuals) [Abstract]        
Maximum duration of hedging of interest rate swap derivative exposure   2 years 1 month    
Maximum duration of hedging of interest rate swap derivative     Less than 4 year  
Number of interest rate swap agreements   4    
Interest rate swap agreements, Aggregate Notional Amounts     $ 140.0  
Interest on New Credit Facility LIBOR + 1.50%+ 2.50% The highest of Federal Funds Rate plus 0.50%, one-month LIBOR plus 1.00%, and the prime rate offered by Bank of America    
Average effective fixed rate on notional balances of debt and interest rate swap, minimum     4.28%  
Average effective fixed rate on notional balances of debt and interest rate swap, maximum     5.28%  
Outstanding Notional Amount of Foreign Currency Forward Contract   33.0   32.1
Derivative Higher Remaining Maturity Range   Next 12 Months    
Number of outstanding foreign currency option contracts   0   0
Foreign exchange currency contracts [Member]
        
Derivative Instruments and Hedging Activities (Textuals)        
Average Remaining Maturity Of Foreign Currency Derivative   Less than twelve months   Less than twelve months
Fair Value of outstanding foreign currency forward contracts       0.6
Interest Rate Swap [Member]
        
Derivative Instruments and Hedging Activities (Textuals)        
Effective date of interest rate swap agreements     Dec. 31, 2009  
Weighted average fixed interest rate on notional amounts     2.78%  
Interest rate applicable on interest rate swap agreements for stipulated period     1 month LIBOR Rate  
Expiration date of interest rate swap agreements     Jul. 01, 2013  
Liabilities related to Interest rate swaps at fair value   $ 6.2   $ 6.6
Freestanding Derivatives [Member]
        
Derivative Instruments and Hedging Activities (Textuals)        
Average Remaining Maturity Of Foreign Currency Derivative   within 1 month   within 3 months