Carrying and Fair Value of Senior Notes (Detail) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Debt Instrument [Line Items]    
Carrying value $ 200,000 $ 200,000
Senior Notes 7.875 Percent Due 2020    
Debt Instrument [Line Items]    
Carrying value 200,000 200,000
Fair value $ 211,000 $ 206,000