Fresh-Start Accounting - Additional Information (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Jul. 31, 2017
Fresh Start Accounting [Line Items]
Enterprise value of successor entity		$ 1,050,000
Enterprise value for deriving equity value		1,055,000
Minimum
Fresh Start Accounting [Line Items]
Enterprise value of successor entity		850,000
Enterprise value for deriving equity value		743,000
Maximum
Fresh Start Accounting [Line Items]
Enterprise value of successor entity		1,250,000
Enterprise value for deriving equity value		$ 1,143,000
Plan of Reorganization
Fresh Start Accounting [Line Items]
Fresh start adjustment, description	Upon our emergence from Chapter 11 bankruptcy, we qualified for and adopted fresh-start accounting in accordance with the provisions set forth in ASC 852 as (i) holders of existing shares of the Predecessor immediately before the Effective Date received less than 50 percent of the voting shares of the Successor entity and (ii) the reorganization value of the Successor was less than its post-petition liabilities and estimated allowed claims immediately before the Effective Date.
Predecessor shareholders percentage of voting shares of successor entity		50.00%
Percentage of weighted average cost of capital		12.00%

$ 1,050,000

850,000

1,250,000

Upon our emergence from Chapter 11 bankruptcy, we qualified for and adopted fresh-start accounting in accordance with the provisions set forth in ASC 852 as (i) holders of existing shares of the Predecessor immediately before the Effective Date received less than 50 percent of the voting shares of the Successor entity and (ii) the reorganization value of the Successor was less than its post-petition liabilities and estimated allowed claims immediately before the Effective Date.

Percentage of weighted average cost of capital

12.00%