Long-Term Debt (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Debt Instrument [Line Items]
Long-term debt	$ 914,126	$ 620,000
6.75% Senior Subordinated Notes due 2014
Debt Instrument [Line Items]
Long-term debt		200,000
8.625% Senior Notes due 2017
Debt Instrument [Line Items]
Long-term debt	375,000	375,000
Senior Convertible Notes due 2017
Debt Instrument [Line Items]
Long-term debt	239,126
7.5% Senior Notes due 2022
Debt Instrument [Line Items]
Long-term debt	300,000
Bank Debt
Debt Instrument [Line Items]
Long-term debt		$ 45,000