Fair Value Measurements (Narrative) (Detail)	Dec. 31, 2017	Dec. 31, 2016	May 13, 2011
Term Loan
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading prices rate to calculate the fair value	86.00%	67.80%
7.75% Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trading prices rate to calculate the fair value	17.38%	40.90%
7.75% Senior Notes
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Interest rate	7.75%	7.75%	7.75%