Exit Activities (Detail) $ in Thousands	1 Months Ended	8 Months Ended	9 Months Ended		12 Months Ended
Exit Activities (Detail) $ in Thousands	Sep. 30, 2016 USD ($)	Sep. 12, 2016 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2016
Predecessor [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated					53
Severance and Termination Benefits			$ 1,900	$ 2,000
Liabilities Subject to Compromise, Early Contract Termination Fees	$ 1,300			1,300
Payments for Restructuring				1,100
Restructuring Reserve, Accretion of Obligation		$ 317		$ 300
Successor [Member]
Restructuring Cost and Reserve [Line Items]
Severance and Termination Adjustment			100
Restructuring Reserve, Accretion of Obligation	$ 0		$ 0