Commitments and Contingencies - Additional Information (Detail) - USD ($) shares in Millions, $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Jul. 31, 2015	Sep. 30, 2015	Sep. 30, 2015	Dec. 31, 2010
Commitments and Contingencies Disclosure [Line Items]
Restructuring advisory fees, shares	6.5
Asset retirement obligations		$ 2.6	$ 2.6
Legal Reserve
Commitments and Contingencies Disclosure [Line Items]
Reserve established for contingency matters				$ 0.9
Contract Drilling
Commitments and Contingencies Disclosure [Line Items]
Contract termination claims description			early termination provisions that would require us to pay penalties if we terminate the agreements prior to the end of their scheduled terms.
Loss on contract termination for default			$ 3.4
Contractual obligation, early termination fee			6.2
Contractual obligation, balance of 2015		2.4	2.4
Contractual obligation, 2016		0.8	0.8
Coil Tubing Services
Commitments and Contingencies Disclosure [Line Items]
Contractual obligation, balance of 2015		1.0	1.0
Firm Transportation
Commitments and Contingencies Disclosure [Line Items]
Contractual obligation, balance of 2015		0.5	0.5
Firm Transportation | Through 2028
Commitments and Contingencies Disclosure [Line Items]
Contractual obligation, annual		$ 1.1	1.1
Firm Transportation | Maximum
Commitments and Contingencies Disclosure [Line Items]
Contract term		13 years
Gas Gathering And Compression Services
Commitments and Contingencies Disclosure [Line Items]
Contractual obligation, balance of 2015		$ 1.1	1.1
Contractual obligation, 2016		5.0	5.0
Crude Oil Gathering And Transportation Services
Commitments and Contingencies Disclosure [Line Items]
Contractual obligation, annual		12.3	12.3
Drilling Carry
Commitments and Contingencies Disclosure [Line Items]
Contractual Obligation		$ 10.7	$ 10.7