Fair Value Measurements (Detail) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
7.75% Senior Notes due 2019, excluding premium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	$ 475,000	$ 475,000
Interest rate	7.75%	7.75%
7.75% Senior Notes due 2022, excluding premium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	$ 300,000	$ 300,000
Interest rate	7.75%	7.75%
Fair Value, Inputs, Level 1 | 7.75% Senior Notes due 2019, excluding premium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	$ 475,000	$ 475,000
Fair Value	180,500	399,000
Fair Value, Inputs, Level 1 | 7.75% Senior Notes due 2022, excluding premium
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	300,000	300,000
Fair Value	84,006	238,500
Fair Value, Inputs, Level 3 | Term Loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying Amount	165,000	0
Fair Value	$ 167,968	$ 0