Indebtedness - Additional Information (Detail) (USD $)	12 Months Ended		0 Months Ended	12 Months Ended			12 Months Ended			12 Months Ended			0 Months Ended	12 Months Ended	0 Months Ended	12 Months Ended	0 Months Ended		12 Months Ended
	Dec. 31, 2013	Oct. 03, 2007	Nov. 04, 2011 Copal	Dec. 31, 2013 Copal	Dec. 31, 2013 2007 Facility	Sep. 28, 2007 2007 Facility	Dec. 31, 2013 Series 2005-1 Notes	Sep. 30, 2005 Series 2005-1 Notes	Dec. 31, 2013 Senior Notes 7.61 Percent Due September 30th 2005	Dec. 31, 2013 Series 2007-1 Notes	Dec. 31, 2013 2010 Senior Notes	Dec. 31, 2013 2012 Senior Notes	Aug. 12, 2013 2013 Senior Notes	Dec. 31, 2013 2013 Senior Notes	Apr. 18, 2012 2012 Facility	Dec. 31, 2013 2012 Facility	Apr. 18, 2012 2012 Facility Minimum	Apr. 18, 2012 2012 Facility Maximum	Dec. 31, 2013 2008 Term Loan	May 31, 2008 2008 Term Loan
Debt Instrument [Line Items]
Date the credit facility was entered					Sep. 28, 2007									Aug. 12, 2013		Apr. 18, 2012
Date of expiry of credit facility					Sep. 27, 2012											Apr. 17, 2017
Senior unsecured revolving credit facility		$ 1,000,000,000				$ 1,000,000,000									$ 1,000,000,000
Interest on borrowings under 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 could range from 125 basis points to 175 basis points LIBOR plus a margin that could 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%
Date of agreement with the lenders for the five year senior unsecured term loan							Sep. 30, 2005			Sep. 07, 2007	Aug. 19, 2010	Aug. 20, 2012							May 07, 2008
Debt, aggregate principal amount								300,000,000	300,000,000	300,000,000	500,000,000	500,000,000	500,000,000						150,000,000
Senior Unsecured Notes, interest							4.98%			6.06%		4.50%	4.875%
Maturity date of Senior Unsecured Notes							Sep. 30, 2015			Sep. 07, 2017	Sep. 01, 2020	Sep. 01, 2022		Sep. 01, 2024
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.
Prepayment and purchase feature of Senior Unsecured Notes							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 being prepaid, plus accrued and unpaid interest and 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 being prepaid, plus accrued and unpaid interest and a Make Whole Amount.	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 amount being prepaid, plus accrued and unpaid interest and a Make-Whole Amount. 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 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. 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 2013 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 2013 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.
Issuance of additional principal amount of Senior Notes within five years from time to time										500,000,000
Percentage of principal amount being prepaid, plus accrued and unpaid interest	100.00%									100.00%
Percentage of principal amount, plus accrued and unpaid interest to the date of purchase											101.00%	101.00%	101.00%
Minimum amount for default on senior notes payable											50,000,000	50,000,000	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 2012 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 2012 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 2013 Indenture, the 2013 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 2013 Indenture, the 2013 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%		25.00%
Non-interest bearing note issued			14,200,000	14,200,000
Interest rate swaps total notional amount																				150,000,000
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 of (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 of (ii) the tenth anniversary date of the issuance of the note
Alternate Prepayment Percentage														100.00%
Aggregate Amount Due At Maturity											$ 50,000,000	$ 50,000,000		$ 50,000,000