Debt - Summary of Debt Instruments (Parenthetical) (Detail)	12 Months Ended		1 Months Ended	12 Months Ended			1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended	1 Months Ended	12 Months Ended		1 Months Ended		12 Months Ended		1 Months Ended						1 Months Ended		12 Months Ended
	Dec. 31, 2013 USD ($)	Dec. 31, 2012	Feb. 03, 2014 Subsequent Event [Member]	Dec. 31, 2013 Minimum [Member]	Dec. 31, 2013 Maximum [Member]	Dec. 31, 2013 Term Note Payable-Domestic, June 22, 2011 [Member] USD ($)	Nov. 06, 2012 Term Note Payable-Domestic, June 22, 2011 [Member] Minimum [Member] USD ($)	Dec. 31, 2013 Term Note Payable-Domestic, June 22, 2011 [Member] Minimum [Member]	Nov. 06, 2012 Term Note Payable-Domestic, June 22, 2011 [Member] Maximum [Member] USD ($)	Dec. 31, 2013 Term Note Payable-Domestic, June 22, 2011 [Member] Maximum [Member]	Mar. 31, 2012 Amended and Restated [Member]	Dec. 31, 2013 Commercial Paper [Member]	Dec. 31, 2012 Commercial Paper [Member]	Feb. 03, 2014 Commercial Paper [Member] Subsequent Event [Member]	Nov. 06, 2012 Term Loan [Member] Term Note Payable-Domestic, June 22, 2011 [Member] USD ($)	Dec. 31, 2013 Term Loan Facility [Member] Term Note Payable-Domestic, June 22, 2011 [Member]	Nov. 06, 2012 Term Loan Facility [Member] Term Note Payable-Domestic, June 22, 2011 [Member] USD ($)	Mar. 20, 2013 Revolving Credit Facility [Member] Term Note Payable-Domestic, June 22, 2011 [Member]	Nov. 06, 2012 Revolving Credit Facility [Member] Term Note Payable-Domestic, June 22, 2011 [Member] USD ($)	Mar. 20, 2013 Line of Credit [Member] Term Note Payable-Domestic, June 22, 2011 [Member] USD ($)	Mar. 20, 2013 Swing Line Loans [Member] Term Note Payable-Domestic, June 22, 2011 [Member] USD ($)	Mar. 20, 2013 Swing Line Loans [Member] Amended and Restated [Member] USD ($)	Mar. 20, 2013 Revolving A Facility [Member] USD ($)	Mar. 31, 2012 Revolving B Facility [Member]	Mar. 20, 2013 Revolving B Facility [Member] USD ($)	Dec. 31, 2013 Eurodollar [Member] Minimum [Member]	Dec. 31, 2013 Eurodollar [Member] Maximum [Member]	Dec. 31, 2013 Foreign Line of Credit New Zealand [Member] NZD
Debt Instrument [Line Items]
Line of credit facility, increase additional borrowings	$ 16,715,000						$ 150,000,000		$ 250,000,000						$ 250,000,000
Increase borrowing limit on revolving line of credit							600,000,000		850,000,000								550,000,000		850,000,000	20,000,000	20,000,000	110,000,000	815,000,000		35,000,000
Debt maturity date																Mar. 01, 2018		Mar. 20, 2018
United Kingdom entities as designated borrowers											Two
Line of credit facility maturity date																								5 years
Interest on the line of credit, sum of rate plus								0.25%		1.25%				0.65%												1.25%	2.25%	1.00%
Principal payments on term loan						28,100,000
Percentage of quarterly commitment fees	0.30%	0.35%	0.25%	0.20%	0.40%
Current purchase limit under the securitization facility	500,000,000
Line of credit charge												0.17%	0.24%															0.025%
Program fee variable rate												0.675%	0.75%
Program fee	One month Libor
Facility utilization limit for unused facility fee	75.00%
Acquisition	$ 9,800,000																											12,000,000
Facility, Maturity date																												Apr. 30, 2014