Debt and Other Obligations - Additional Information (Detail) (USD $)	9 Months Ended				9 Months Ended			1 Months Ended			9 Months Ended		9 Months Ended			1 Months Ended	9 Months Ended	1 Months Ended				1 Months Ended			1 Months Ended			9 Months Ended
	Oct. 08, 2011	Oct. 06, 2012	Jul. 21, 2012	Dec. 31, 2011	Oct. 06, 2012 Minimum	Oct. 06, 2012 Maximum	Oct. 06, 2012 Letter of Credit	Apr. 03, 2012 Indenture	Apr. 03, 2012 Indenture Prior To January First Two Thousand And Twenty Two	Apr. 03, 2012 Indenture Change Of Control Triggering Event	Oct. 06, 2012 Senior Notes	Mar. 28, 2012 Senior Notes	Oct. 06, 2012 Redeemable Senior Notes	Oct. 06, 2012 Standby Letters of Credit	Dec. 31, 2011 Standby Letters of Credit	May 20, 2011 Former Credit Facility	Oct. 06, 2012 Former Credit Facility	May 20, 2011 New Credit Facility Y	Oct. 06, 2012 New Credit Facility	Dec. 31, 2011 New Credit Facility	May 20, 2011 New Credit Facility Federal Funds Rate	May 20, 2011 New Credit Facility Minimum	May 20, 2011 New Credit Facility Minimum Base Rate Loans	May 20, 2011 New Credit Facility Minimum Eurodollar Loans	May 20, 2011 New Credit Facility Maximum	May 20, 2011 New Credit Facility Maximum Base Rate Loans	May 20, 2011 New Credit Facility Maximum Eurodollar Loans	Oct. 06, 2012 Revolving Credit Facility
Debt Instrument [Line Items]
Bank overdraft balance		$ 13,500,000		$ 10,200,000
Line of credit facility, outstanding borrowings							15,600,000							15,600,000	14,700,000				106,600,000	225,000,000
Interest rate											4.375%	4.375%
Term loan borrowed amount		150,000,000	20,000,000					400,000,000
Price to redeem notes as a percentage of principal								100.00%	100.00%	101.00%
Variable interest rate								0.35%
Term loan maturity date											Apr. 01, 2022		Jan. 01, 2022
Repayment of long-term debt, amount																	207,200,000
Discount on notes			2,300,000					900,000
Payment of financing fees	2,108,000							3,900,000										2,000,000
Credit facility, number of one-year extensions																		2
Credit facility, duration of extension term (in years)																		1
Line of credit facility, maximum borrowing capacity																		700,000,000
Line of credit facility, amount available		377,800,000																500,000,000
Basis spread on variable rate																					0.50%		0.30%	1.30%		1.25%	2.25%
Minimum interest rate in addition to interbank Eurodollar market rate																		1.00%
Facility fee range																						0.20%			0.50%
Financing costs																		1,000,000
Amortization of financing costs																100,000
Line of credit facility outstanding daily balance during period					0	230,000,000
Line of credit facility, borrowings																												780,100,000
Line of credit facility, repaid borrowings																												$ 898,500,000