Long-Term Debt Activity - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended		6 Months Ended		1 Months Ended	6 Months Ended		1 Months Ended	3 Months Ended	6 Months Ended				6 Months Ended			6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 5.125% senior notes due 2022	Dec. 18, 2012 5.125% senior notes due 2022	May 24, 2013 4.875 % Senior Notes Due May 2023	Jun. 30, 2013 4.875 % Senior Notes Due May 2023	Jun. 30, 2013 8.625% senior note due 2019	Jun. 24, 2013 8.625% senior note	Jun. 30, 2013 8.625% senior note	Jun. 30, 2013 8.625% senior note	Jun. 30, 2013 Amended Senior Secured Credit Facility	Jun. 30, 2013 Term Loan Credit Facilty Amended Senior Secured Credit Facility	Dec. 18, 2012 Term Loan Credit Facilty Amended Senior Secured Credit Facility	Jun. 30, 2013 Term Loan Credit Facilty Amended Senior Secured Credit Facility Quarterly Principle Payment	Jun. 30, 2013 Term Loan Credit Facilty Amended Senior Secured Credit Facility Quarterly Principle Payment Maximum	Dec. 18, 2012 Term Loan Credit Facilty Amended Senior Secured Credit Facility Remaining principal due on December 18, 2019	Jun. 30, 2013 Revolving Credit Line Amended Senior Secured Credit Facility	Dec. 18, 2012 Revolving Credit Line Amended Senior Secured Credit Facility
Debt Instrument [Line Items]
Aggregate principal amount issued					$ 400,000	$ 530,000								$ 700,000			$ 652,750		$ 100,000
Maturity year				2022			2023	2019
Interest rate					5.125%	4.875%
Debt instrument, maturity date				Dec. 15, 2022			Jun. 01, 2023					Dec. 18, 2019
Debt issuance cost		9,212				8,230
Price to repurchase the senior subordinated notes as a percentage of the aggregate principal amount outstanding plus accrued and unpaid interest in case of change of control							101.00%
Maximum percentage of principal amount of the senior subordinated notes that can be redeemed prior to specific date							35.00%
Price to repurchase the senior subordinated notes as a percentage of principal amount plus a make-whole premium in case of redemption at option of company prior to specific date							100.00%
Registration Statement maximum required period to have registration statement declared effective							Jul. 09, 2013
Principal debt repayment		461,946							470,000
Percentage of debt repayment premium											112.035%
Write off of unamortization of bond discount										8,054	8,054
Write off of unamortization of debt issuance cost											7,634
Early retirement of debt											56,564
Loss on early retirement of debt	72,302	72,302								50	50
Maturity period													7 years					5 years
Quarterly principal payments due															1,750
Maturity date													2019-12			2019-09		2017-12
Carrying value of long-term debt	1,827,651	1,827,651	1,764,010
Fair value of long-term debt	$ 1,808,951	$ 1,808,951	$ 1,851,246