Income Taxes (Narrative) (Detail) - USD ($) $ in Thousands	3 Months Ended	5 Months Ended	7 Months Ended	12 Months Ended
	Dec. 31, 2018	Jun. 03, 2018	Dec. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes [Line Items]
Deferred income tax liabilities decrease				$ 10,600
Increase for prior year positions	$ 900			900
Valuation allowance					$ 75,500
Interest and penalties related to unrecognized tax benefits		$ 100	$ 300		1,800
Unrecognized tax benefits accrued interest and penalties	100	$ 400	100	100	$ 300
Total unrecognized tax benefits and accrued interest and penalties	5,800		5,800	5,800
Unrecognized tax benefits if recognized will would affect tax rate	5,800		5,800	5,800
Unrecognized tax benefits which are not expected to change significantly within the next 12 months	300		300	300
State and Local Jurisdiction
Income Taxes [Line Items]
Net operating loss carryforwards	41,100		41,100	41,100
Internal Revenue Service (IRS)
Income Taxes [Line Items]
Net operating loss carryforwards	37,800		$ 37,800	37,800
Successor
Income Taxes [Line Items]
Federal statutory income tax rate			21.00%
Increase for prior year positions			$ 0
Valuation allowance	$ 0		$ 0	$ 0
Predecessor
Income Taxes [Line Items]
Federal statutory income tax rate		21.00%			35.00%	35.00%
Increase for prior year positions		$ 176			$ 447
Valuation allowance					$ 75,460