Long-Term Debt - Cash and Non-Cash Portion of Interest Expense Related to Long Term Debt (Detail) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Principal	$ 625,000,000	$ 626,859,000
7.625% Senior Notes [Member]
Debt Instrument [Line Items]
Debt, stated interest rate	7.625%
Principal			$ 315,300,000
7.0% Senior Notes [Member]
Debt Instrument [Line Items]
Debt, stated interest rate	7.00%
Principal	$ 350,000,000.0	350,000,000
Lease Financing Obligation [Member]
Debt Instrument [Line Items]
Principal	$ 1,859,000	$ 2,328,000