Quarterly report pursuant to Section 13 or 15(d)

Debt - Additional Information (Detail)

v2.4.0.8
Debt - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended 12 Months Ended 9 Months Ended 12 Months Ended 9 Months Ended 12 Months Ended 9 Months Ended 12 Months Ended
Dec. 31, 2011
Jun. 30, 2013
Dec. 31, 2012
Dec. 31, 2011
Federal Funds Rate
Sep. 30, 2012
LIBOR
Dec. 31, 2011
LIBOR
Sep. 30, 2012
LIBOR
Minimum
Dec. 31, 2011
LIBOR
Minimum
Sep. 30, 2012
LIBOR
Maximum
Dec. 31, 2011
LIBOR
Maximum
Dec. 31, 2011
Wells fargo's prime rate
Dec. 31, 2011
Wells fargo's prime rate
Minimum
Dec. 31, 2011
Wells fargo's prime rate
Maximum
Dec. 31, 2011
Standby Letters of Credit
Dec. 31, 2011
Revolving Credit Facility
Line of Credit Facility [Line Items]                              
Sub limit for issuance of letters of credit                           $ 10.0  
Revolving line of credit facility, available borrowing capacity   150.0                         150.0
Principal together with accrued and unpaid interest due and payable, date Dec. 30, 2015                            
Interest rate descriptions Revolving loans accrue interest at a per annum rate equal to, at the Company's option, either LIBOR or Wells Fargo's prime rate (or, if greater, the federal funds rate plus 0.50% or three month LIBOR plus 1.00%), in each case plus a margin ranging from 2.50% to 3.00%, in the case of LIBOR loans, and 0.00% to 0.25% in the case of prime rate loans, based upon the Company's senior leverage ratio.     The federal funds rate plus 0.50% The terms of the amendment, the LIBOR rate margin ranges from 2.00% to 2.50%, based on our senior leverage ratio 2.50% to 3.00% plus LIBOR         0.00% to 0.25% plus Wells Fargo's prime rate        
Basis spread on interest rate       0.50%   1.00% 2.00% 2.50% 2.50% 3.00%   0.00% 0.25%    
Revolving line of credit, outstanding amount   0 10.0                        
Unamortized debt issuance costs   0.5 0.8                        
Issuance of letters of credit outstanding, amount   $ 10.0