Fair Value Measurements - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Nov. 27, 2013	Dec. 31, 2012
8.625 % Senior Notes Due 2017 [Member]
Debt Instrument [Line Items]
Long term debt, Fair Value			$ 401,250
Convertible Notes Due 2017 [Member]
Debt Instrument [Line Items]
Liability component of convertible note	260,377		249,601
7.5% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Liability component of convertible note	814,719		314,250
Aggregate principal amount of senior notes		$ 475,000