Fresh Start Accounting (Narrative) (Detail) - USD ($)			1 Months Ended	3 Months Ended
	Feb. 08, 2019	Dec. 28, 2017	Feb. 08, 2019	Mar. 31, 2019	Dec. 31, 2018
Fresh-Start Adjustment [Line Items]
Enterprise value	$ 155,000,000		$ 155,000,000
Oil and gas properties, full cost method	52,070,000		52,070,000
Unproven reserves, fair value	99,000,000		99,000,000
Undeveloped acreage, fair value	19,700,000		19,700,000
Asset retirement obligation	$ 2,500,000		2,500,000
Discount credit adjusted risk free rate	10.00%
Common stock, shares outstanding (in shares)				9,371,000
Common stock, par value (in dollars per share)				$ 0.01
Minimum
Fresh-Start Adjustment [Line Items]
Enterprise value	$ 104,000,000		104,000,000
Estimated enterprise value plus cash	117,000,000		117,000,000
Maximum
Fresh-Start Adjustment [Line Items]
Enterprise value	187,000,000		187,000,000
Estimated enterprise value plus cash	$ 200,000,000		200,000,000
10% Senior Secured Notes due 2021
Fresh-Start Adjustment [Line Items]
Shares issued (in shares)		2,200,000
Extinguishment of debt, amount		$ 4,800,000
Exit Facility
Fresh-Start Adjustment [Line Items]
Discounted cash flow, credit spread percent	10.10%			10.10%
10% Secured PIK Notes due 2024
Fresh-Start Adjustment [Line Items]
Discounted cash flow, credit spread percent	11.90%			11.90%
Predecessor
Fresh-Start Adjustment [Line Items]
Payment of professional fees at emergence			$ (5,398,000)
Common stock, shares outstanding (in shares)					25,587,000
Common stock, par value (in dollars per share)					$ 0.001
Common Class A | Common Stock | Class C Holder
Fresh-Start Adjustment [Line Items]
Common stock, par value (in dollars per share)	$ 0.01		$ 0.01
Common Class A | Cancellation And Discharge Of Old Notes | Common Stock | Former Holders Of Old Notes
Fresh-Start Adjustment [Line Items]
Shares issued (in shares)	8,900,000
Common Class A | Commitment To Backstop Exit Facility | Common Stock | Consenting Creditors
Fresh-Start Adjustment [Line Items]
Shares issued (in shares)	300,000
Common Class A | Commitment To Backstop Exit Facility | Common Stock | Holders Of Stock Awards Which Vested At Emergence
Fresh-Start Adjustment [Line Items]
Shares issued (in shares)	263,599
Common Class C | Common Stock | Class C Holder
Fresh-Start Adjustment [Line Items]
Shares issued (in shares)	1
Common Class B | Common Stock | Class B Holder
Fresh-Start Adjustment [Line Items]
Shares issued (in shares)	1
2019 Long Term Incentive Plan | Restricted Stock Units (RSUs) | Fully Vested Upon Grant | Common Stock | Weighted Average
Fresh-Start Adjustment [Line Items]
Shares retired (in shares)	92,479
Common stock, shares outstanding (in shares)	171,120		171,120
Payment in Kind (PIK) Note | 10% Senior Secured Notes due 2021
Fresh-Start Adjustment [Line Items]
Stated interest rate	10.00%		10.00%
Payment in Kind (PIK) Note | 10% Senior Secured PIK Notes due 2021
Fresh-Start Adjustment [Line Items]
Stated interest rate	10.00%		10.00%
Payment in Kind (PIK) Note | 10% Secured PIK Notes due 2024
Fresh-Start Adjustment [Line Items]
Stated interest rate	10.00%		10.00%
Payment in Kind (PIK) Note | Cancellation And Discharge Of Old Notes | Former Holders Of Old Notes | 10% Secured PIK Notes due 2024
Fresh-Start Adjustment [Line Items]
Stated interest rate	10.00%		10.00%
Term Loan | Line of Credit | Multidraw Term Loan Agreement
Fresh-Start Adjustment [Line Items]
Extinguishment of debt, amount	$ 50,000,000
Term Loan | Line of Credit | Exit Facility
Fresh-Start Adjustment [Line Items]
Maximum borrowing capacity	$ 50,000,000		$ 50,000,000
Measurement Input, Discount Rate | Valuation, Income Approach
Fresh-Start Adjustment [Line Items]
Fair value of proved and probable reserves, weighted average cost of capital, percentage	13.00%