Quarterly report pursuant to Section 13 or 15(d)

Debt (Details)

v2.4.0.6
Debt (Details) (USD $)
3 Months Ended 9 Months Ended 9 Months Ended 9 Months Ended
Sep. 30, 2012
Sep. 30, 2011
Sep. 30, 2012
Sep. 30, 2011
Dec. 31, 2011
Sep. 30, 2012
Term loan [Member]
Dec. 31, 2011
Term loan [Member]
Jul. 31, 2011
Term loan [Member]
Sep. 30, 2012
Letters of Credit [Member]
Dec. 31, 2011
Letters of Credit [Member]
Sep. 30, 2012
Revolving Loans [Member]
Dec. 31, 2011
Revolving Loans [Member]
Sep. 30, 2011
Revolving Loans [Member]
Debt Instrument [Line Items]                          
Debt Instrument, Maturity Date     Jun. 30, 2016                    
Financing costs     $ 1,700,000                    
Borrowings outstanding           96,800,000 110,900,000            
Term loan payments, 2012           4,700,000              
Term loan payments 2013           23,400,000              
Term loan payments 2014           25,000,000              
Term loan payments 2015           34,300,000              
Term loan payments 2016           9,400,000              
Revolving loans maximum borrowing capacity                     125,000,000    
Revolving loans potential increment in maximum borrowing capacity                     175,000,000    
Debt outstanding 148,800,000   148,800,000   164,200,000                
Revolving loans amount outstanding                     52,000,000 53,300,000  
Letters of credit outstanding                 1,300,000 5,000,000      
Debt Instrument, Description of Variable Rate Basis     LIBOR base margin 0.50%                    
Debt Instrument, Basis Spread on Variable Rate 2.25%   2.25%                    
Duration of interest rate cash flow hedge (in years)           3 years         2 years    
Amount of interest rate hedge               101,000,000     20,000,000 40,000,000 40,000,000
Effective interest rate on the hedged term debt           0.56% plus base margin         0.7775% plus base margin    
Interest rate range, minimum (in hundredths)     2.47%                    
Interest rate range, maximum (in hundredths)     3.87%                    
Effective interest rate (in hundredths) 3.33%   3.33%                    
Interest expense, net $ 1,400,000 $ 1,300,000 $ 3,900,000 $ 1,900,000