Annual report pursuant to Section 13 and 15(d)

Fair Value of Financial Instruments - Fair Values and Related Carrying Values of Debt Instruments (Detail)

v3.3.1.900
Fair Value of Financial Instruments - Fair Values and Related Carrying Values of Debt Instruments (Detail) - USD ($)
$ in Thousands
Dec. 31, 2015
Dec. 31, 2014
Carrying Amount [Member]    
Long-term Debt    
Long-term Debt $ 585,000 $ 585,000
Carrying Amount [Member] | 6.75 % Senior Notes [Member]    
Long-term Debt    
Long-term Debt 360,000 360,000
Carrying Amount [Member] | 7.50% Senior Notes, due August 2020 (Issued July 30, 2013) [Member]    
Long-term Debt    
Long-term Debt 225,000 225,000
Fair Value [Member]    
Long-term Debt    
Long-term Debt 417,600 450,000
Fair Value [Member] | 6.75 % Senior Notes [Member]    
Long-term Debt    
Long-term Debt 246,600 270,000
Fair Value [Member] | 7.50% Senior Notes, due August 2020 (Issued July 30, 2013) [Member]    
Long-term Debt    
Long-term Debt $ 171,000 $ 180,000