Long-Term Debt Activity - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended			6 Months Ended		6 Months Ended		0 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 4.875 % Senior Notes Due May 2023	May 24, 2013 4.875 % Senior Notes Due May 2023	Jun. 30, 2014 8.625% senior note due 2019	May 24, 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. 24, 2013 8.625% senior note
Debt Instrument [Line Items]
Aggregate principal amount issued						$ 530,000
Maturity year					2023		2019
Interest rate						4.875%		8.625%				8.625%
Debt instrument, maturity date					Jun. 01, 2023
Principal amount of redeemed senior notes at maturity									470,000
Percentage of debt repayment premium											112.035%
Discount on issue										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
Carrying value of long-term debt			1,827,833	1,832,800
Fair value of long-term debt			$ 1,860,094	$ 1,815,879