Quarterly report pursuant to Section 13 or 15(d)

Line of Credit - Additional Information (Detail)

v2.4.0.6
Line of Credit - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
 1 Months Ended 1 Months Ended
Sep. 30, 2012
Sep. 30, 2012
Minimum
Oct. 29, 2012
Eleventh Amendment to Ninth Amended and Restated Credit Agreement
Oct. 30, 2012
Eleventh Amendment to Ninth Amended and Restated Credit Agreement
Line of Credit Facility [Line Items]        
Revolving credit facility, maximum borrowing capacity $ 60   $ 80  
Revolving credit facility, expiration date Dec. 31, 2013   Dec. 31, 2014  
Revolving credit facility, interest rate description     Amounts borrowed under the revolver bear interest, at our option, at the prime lending rate established by JPMorgan Chase Bank, N.A. or LIBOR plus 1.5 percent. We pay a fee on a quarterly basis of one-fourth of one percent per annum on the weighted-average unused portion of the revolver.  
Revolving credit facility, interest rate above LIBOR     1.50%  
Revolving credit facility, unused quarterly commitment fee     0.25%  
Total outstanding letters of credit       41.9
Revolving credit facility, unused portion       $ 38.1
Line of credit covenant, current ratio   1.25    
Line of credit covenant, debt to net worth   0.5    
Line of credit covenant, Earnings before interest, taxes, depreciation and amortization (EBITDA) to interest expense ratio 4.0