Debt - Summary of Debt Instruments (Parenthetical) (Detail) | 3 Months Ended | 12 Months Ended | 3 Months Ended | | | | 1 Months Ended | 3 Months Ended | 1 Months Ended | 3 Months Ended | 0 Months Ended | 3 Months Ended | 12 Months Ended | 1 Months Ended | 3 Months Ended | | 1 Months Ended | | | 0 Months Ended | | 3 Months Ended |
In Millions, unless otherwise specified | Mar. 31, 2014 | Dec. 31, 2013 | Mar. 31, 2014 | Mar. 31, 2014 | Mar. 31, 2014 | Nov. 06, 2012 | Jun. 22, 2011 | Nov. 06, 2012 | Mar. 31, 2014 | Nov. 06, 2012 | Mar. 31, 2014 | Mar. 13, 2012 | Mar. 31, 2014 | Dec. 31, 2013 | Nov. 06, 2012 | Mar. 31, 2014 | Nov. 06, 2012 | Mar. 20, 2013 | Nov. 06, 2012 | Mar. 20, 2013 | Mar. 20, 2013 | Mar. 20, 2013 | Mar. 20, 2013 | Mar. 13, 2012 | Mar. 20, 2013 | Mar. 31, 2014 | Mar. 31, 2014 | Mar. 31, 2014 |
| USD ($) | USD ($) | Minimum [Member] | Maximum [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Amended and Restated [Member] | Commercial Paper [Member] | Commercial Paper [Member] | Term Loan [Member] | Term Loan Facility [Member] | Term Loan Facility [Member] | Revolving Credit Facility [Member] | Revolving Credit Facility [Member] | Letter of Credit [Member] | Swing Line Loans [Member] | Swing Line Loans [Member] | Revolving A Facility [Member] | Revolving B Facility [Member] | Revolving B Facility [Member] | Eurodollar [Member] | Eurodollar [Member] | Foreign Line of Credit New Zealand [Member] |
| | | | | USD ($) | USD ($) | USD ($) | Minimum [Member] | Minimum [Member] | Maximum [Member] | Maximum [Member] | | | | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Term Note Payable-Domestic, June 22, 2011 [Member] | Amended and Restated [Member] | USD ($) | | USD ($) | Minimum [Member] | Maximum [Member] | NZD |
| | | | | | | | USD ($) | | USD ($) | | | | | USD ($) | | USD ($) | | USD ($) | USD ($) | USD ($) | USD ($) | | | | | | |
Debt Instrument [Line Items] | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Line of credit facility, increase additional borrowings | ' | ' | ' | ' | ' | ' | ' | $150 | ' | $250 | ' | ' | ' | ' | $250 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Increase borrowing limit on revolving line of credit | ' | ' | ' | ' | ' | 850 | 600 | ' | ' | ' | ' | ' | ' | ' | ' | ' | 550 | ' | 850 | 20 | 20 | 110 | 815 | ' | 35 | ' | ' | ' |
Debt maturity date | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 1-Mar-18 | ' | 20-Mar-18 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
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% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 1.25% | 2.25% | 1.00% |
Principal payments on term loan | ' | ' | ' | ' | 6.9 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Percentage of quarterly commitment fees | 0.25% | 0.30% | 0.20% | 0.40% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Current purchase limit under the securitization facility | 500 | 500 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Line of credit charge | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 0.17% | 0.17% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 0.03% |
Program fee variable rate | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 0.65% | 0.68% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Acquisition | $10.40 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 12 |
Facility, Maturity date | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 30-Apr-14 |