Indebtedness - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended			3 Months Ended			3 Months Ended		0 Months Ended	3 Months Ended	0 Months Ended		3 Months Ended
	Oct. 03, 2007	Mar. 31, 2013	Mar. 31, 2013 Copal [Member]	Sep. 28, 2007 Two Thousand And Seven Revolving Credit Facility [Member]	Mar. 31, 2013 Twenty Ten Senior Notes [Member]	Mar. 31, 2013 Series Two Thousand Five Dash One Notes [Member]	Sep. 30, 2005 Series Two Thousand Five Dash One Notes [Member]	Mar. 31, 2013 Series Two Thousand Seven Dash One Notes [Member]	Mar. 31, 2013 Senior Notes Seven Point Six One Percent Due September Thirty Two Thousand Five [Member]	Apr. 18, 2012 Two Thousand Twelve Facility [Member]	Mar. 31, 2013 Two Thousand Twelve Facility [Member]	Apr. 18, 2012 Two Thousand Twelve Facility [Member] Minimum [Member]	Apr. 18, 2012 Two Thousand Twelve Facility [Member] Maximum [Member]	Mar. 31, 2013 Twenty Twelve Senior Notes [Member]	Mar. 31, 2013 Term Loan Two Thousand Eight [Member]
Debt Instrument [Line Items]
Senior unsecured revolving credit facility	$ 1,000,000,000			$ 1,000,000,000						$ 1,000,000,000
Interest on borrowings under the Term Loan										LIBOR plus a premium that can range from 77.5 basis points to 120 basis points per annum LIBOR plus a premium that can range from 77.5 basis points to 120 basis points per annum					LIBOR plus a margin that can range from 125 basis points to 175 basis points LIBOR plus a margin that can range from 125 basis points to 175 basis points
Quarterly facility fees											range from 10 basis points of the facility amount to 17.5 basis points range from 10 basis points of the facility amount to 17.5 basis points
Interest rate, LIBOR marginal basis points												77.50%	120.00%
Facility quarterly fee, basis points per annum												10.00%	17.50%
Debt to EBITDA ratio not to exceed at the end of any fiscal quarter								The Company must also not permit its Debt/EBITDA ratio to exceed 4.0 to 1.0 at the end of any fiscal quarter The Company must also not permit its Debt/EBITDA ratio to exceed 4.0 to 1.0 at the end of any fiscal quarter			Debt to EBITDA Ratio of not more than 4 to 1 at the end of any fiscal quarter Debt to EBITDA Ratio of not more than 4 to 1 at the end of any fiscal quarter				Debt/EBITDA ratio of not more than 4.0 to 1.0 at the end of any fiscal quarter Debt/EBITDA ratio of not more than 4.0 to 1.0 at the end of any fiscal quarter
Maturity date of CP Notes (in days)	397 397
Non-interest bearing note issued			14,200,000
Notes due description			(i) the fourth anniversary date of the note or (ii) within a time frame set forth in the acquisition agreement relating to the resolution of certain income tax uncertainties pertaining to the transaction (i) the fourth anniversary date of the note or (ii) within a time frame set forth in the acquisition agreement relating to the resolution of certain income tax uncertainties pertaining to the transaction
Notes repayment description			(i) two business days subsequent to the exercise of the put/call option to acquire the remaining shares of Copal or (ii) the tenth anniversary date of the issuance of the note (i) two business days subsequent to the exercise of the put/call option to acquire the remaining shares of Copal or (ii) the tenth anniversary date of the issuance of the note
Debt, aggregate principal amount							300,000,000	300,000,000	300,000,000					500,000,000	150,000,000
Senior Unsecured Notes, interest					50.00%	4.98%		6.06%	7.61%					4.50%
Prepayment and purchase feature of Senior Unsecured Notes					The Company may prepay the 2010 Senior Notes, in whole or in part, at any time at a price equal to 100% of the principal The Company may prepay the 2010 Senior Notes, in whole or in part, at any time at a price equal to 100% of the principal	In the event that Moody’s pays all, or part, of the Series 2005-1 Notes in advance of their maturity, such prepayment will be subject to a Make Whole Amount In the event that Moody’s pays all, or part, of the Series 2005-1 Notes in advance of their maturity, such prepayment will be subject to a Make Whole Amount		The Company may prepay the Series 2007-1 Notes, in whole or in part, at any time at a price equal to 100% of the principal amount The Company may prepay the Series 2007-1 Notes, in whole or in part, at any time at a price equal to 100% of the principal amount						The Company may prepay the 2012 Senior Notes, in whole or in part, at any time at a price equal to 100% of the principal amount being prepaid, plus accrued and unpaid interest and a Make-Whole Amount The Company may prepay the 2012 Senior Notes, in whole or in part, at any time at a price equal to 100% of the principal amount being prepaid, plus accrued and unpaid interest and a Make-Whole Amount
Percentage of principal amount being prepaid, plus accrued and unpaid interest		100.00%
Percentage of principal amount, plus accrued and unpaid interest to the date of purchase					101.00%									101.00%
Minimum amount for default on senior notes payable		50,000,000
Minimum percentage for default on senior notes payable					Upon the occurrence and during the continuation of an event of default under the 2010 Indenture, the notes may become immediately due and payable either automatically or by the vote of the holders of more than 25% of the aggregate principal amount of all of the notes then outstanding. Upon the occurrence and during the continuation of an event of default under the 2010 Indenture, the notes may become immediately due and payable either automatically or by the vote of the holders of more than 25% of the aggregate principal amount of all of the notes then outstanding.									Upon the occurrence and during the continuation of an event of default under the Indenture, the 2012 Senior notes may become immediately due and payable either automatically or by the vote of the holders of more than 25% of the aggregate principal amount of all of the notes then outstanding Upon the occurrence and during the continuation of an event of default under the Indenture, the 2012 Senior notes may become immediately due and payable either automatically or by the vote of the holders of more than 25% of the aggregate principal amount of all of the notes then outstanding
Minimum percentage of aggregate principal amount of all notes					25.00%									25.00%
Issuance of additional principal amount of Senior Notes within five years from time to time								500,000,000
Interest rate swaps total notional amount															$ 150,000,000