Exit Activities (Detail) $ in Millions	9 Months Ended
	Sep. 30, 2016 USD ($) contract
Restructuring and Related Activities [Abstract]
Restructuring and Related Cost, Number of Positions Eliminated	45
Severance and Termination Benefits Paid	$ 1.9
Severance and Termination Benefits	1.2
Severance and Termination Benefits Expected	$ 0.1
Restructuring and Related Cost, Expected Number of Positions Eliminated	9
Retention Bonuses Expected	$ 0.2
Retention Bonuses	0.7
Severance, Termination and Retention Benefits Expected	$ 0.3
Number Of Drilling Rig Contracts Terminated | contract	1
Liabilities Subject to Compromise, Early Contract Termination Fees	$ 1.3