Long-Term Debt - Additional Information (Detail)	6 Months Ended
Jun. 30, 2018 USD ($) Day $ / shares	Jun. 30, 2017 USD ($) shares
Debt Instrument [Line Items]
Interest rate on senior notes, payment in kind	12.25%
Additional notes outstanding	$ 91,900,000
10% Senior Secured Toggle Notes due 2020
Debt Instrument [Line Items]
Interest payment terms	payable on March 15 and September 15
Maturity of senior notes	Mar. 15, 2020
Accrued interest by issuing additional notes	$ 75,000,000
Interest rate on senior notes	10.00%
10% Senior Notes due 2020
Debt Instrument [Line Items]
Interest payment terms	payable on March 15 and September 15
Maturity of senior notes	Mar. 15, 2020
Interest rate on senior notes	10.00%
7¾% Convertible Second Lien PIK Notes due 2019
Debt Instrument [Line Items]
Interest payment terms	payable on April 1 and October 1
Maturity of senior notes	Apr. 01, 2019
Interest rate on senior notes	7.75%
7¾% Senior Notes due 2019
Debt Instrument [Line Items]
Interest payment terms	payable on April 1 and October 1
Maturity of senior notes	Apr. 01, 2019
Interest rate on senior notes	7.75%
9½% Convertible Second Lien PIK Notes due 2020
Debt Instrument [Line Items]
Interest payment terms	payable on June 15 and December 15
Maturity of senior notes	Jun. 15, 2020
Interest rate on senior notes	9.50%
Convertible Second Lien PIK Notes
Debt Instrument [Line Items]
Debt instrument convertible conversion ratio	0.0812
Debt instrument convertible threshold consecutive trading days period \| Day	15
Convertible Second Lien PIK Notes \| Minimum
Debt Instrument [Line Items]
Daily volume weighted average price \| $ / shares	$ 12.32
Converted Notes
Debt Instrument [Line Items]
Debt instrument, principal amount and accrued interest		$ 9,900,000
Common stock shares exchanged for repayment of principal amount \| shares		826,327
9½% Senior Notes due 2020
Debt Instrument [Line Items]
Interest payment terms	payable on June 15 and December 15
Maturity of senior notes	Jun. 15, 2020
Interest rate on senior notes	9.50%

Daily volume weighted average price.

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- Definition

Debt conversion principal amount plus accrued interest.

+ References

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Debt instrument, interest rate, payment in kind.

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Maximum accrued interest payable in kind.

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Maximum notes issuable for toggle interest paid in kind.

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- Definition

The number of shares issued in exchange for the original debt being converted in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or payments in the period.

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Ratio applied to the conversion of debt instrument into equity with equity shares divided by debt principal amount.

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Threshold period of specified consecutive trading days within which common stock price to conversion price of convertible debt instrument must exceed threshold percentage for specified number of trading days to trigger conversion feature.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Date when the debt instrument is scheduled to be fully repaid, in CCYY-MM-DD format.

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Description of the payment terms of the debt instrument (for example, whether periodic payments include principal and frequency of payments) and discussion about any contingencies associated with the payment.

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