Long-Term Debt Activity - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	9 Months Ended		1 Months Ended	9 Months Ended		1 Months Ended	9 Months Ended			9 Months Ended			9 Months Ended			9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	May 24, 2013 4.875 % Senior Notes Due May 2023	Sep. 30, 2013 4.875 % Senior Notes Due May 2023	Sep. 30, 2013 8.625% senior note due 2019	Jun. 24, 2013 8.625% senior note	Sep. 30, 2013 8.625% senior note	Sep. 30, 2013 5.125% senior notes due 2022	Dec. 18, 2012 5.125% senior notes due 2022	Sep. 30, 2013 Amended Senior Secured Credit Facility	Sep. 30, 2013 Term Loan Credit Facility Amended Senior Secured Credit Facility	Dec. 18, 2012 Term Loan Credit Facility Amended Senior Secured Credit Facility	Sep. 30, 2013 Term Loan Credit Facility Amended Senior Secured Credit Facility Quarterly Principal Payment	Sep. 30, 2013 Term Loan Credit Facility Amended Senior Secured Credit Facility Quarterly Principal Payment Maximum	Dec. 18, 2012 Term Loan Credit Facility Amended Senior Secured Credit Facility Remaining principal due on December 18, 2019	Sep. 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			$ 530,000						$ 400,000			$ 700,000			$ 652,750		$ 100,000
Maturity year				2023	2019			2022
Interest rate			4.875%						5.125%
Debt instrument, maturity date				Jun. 01, 2023				Dec. 15, 2022		Dec. 18, 2019
Debt issuance cost	9,328		8,258
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%
Date on which registration of senior notes became 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
Write off of unamortization of debt issuance cost							7,634
Early retirement of debt							56,564
Loss on early retirement of debt	72,302						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	1,826,764	1,764,010
Fair value of long-term debt	$ 1,780,457	$ 1,851,246