Divestitures	12 Months Ended
Dec. 31, 2016
Acquisitions and divestitures [Abstract]
Divestitures	DIVESTITURES Oil and Natural Gas We had non-core asset sales with proceeds, net of related expenses, of $33.1 million, $1.9 million, and $67.2 million in 2014, 2015, and 2016, respectively. Proceeds from these dispositions reduced the net book value of the full cost pool with no gain or loss recognized. Contract Drilling During 2014, we sold four drilling rigs to an unaffiliated third party. The proceeds of this sale, less costs to sell, exceeded the $16.3 million net book value of the drilling rigs, both in the aggregate and for each drilling rig, resulting in a gain of $9.6 million. During the first quarter of 2015, we sold one drilling rig to an unaffiliated third party for $0.3 million resulting in a gain of $7,900. During the third quarter, we sold 30 drilling rigs, some old top drive equipment, and drill pipe in an auction. The proceeds from the sale of those assets, less costs to sell, was less than the $11.0 million net book value resulting in a loss of $7.3 million pre-tax. During December 2016, we sold one idle 1500 HP SCR drilling rig to an unaffiliated third party. The proceeds of this sale, less costs to sell, exceeded the $1.7 million net book value of the drilling rig, resulting in a gain of $1.6 million.

Divestitures

12 Months Ended

Dec. 31, 2016

Acquisitions and divestitures [Abstract]

DIVESTITURES

Oil and Natural Gas

We had non-core asset sales with proceeds, net of related expenses, of $33.1 million, $1.9 million, and $67.2 million in 2014, 2015, and 2016, respectively. Proceeds from these dispositions reduced the net book value of the full cost pool with no gain or loss recognized.

Contract Drilling

During 2014, we sold four drilling rigs to an unaffiliated third party. The proceeds of this sale, less costs to sell, exceeded the $16.3 million net book value of the drilling rigs, both in the aggregate and for each drilling rig, resulting in a gain of $9.6 million.

During the first quarter of 2015, we sold one drilling rig to an unaffiliated third party for $0.3 million resulting in a gain of $7,900. During the third quarter, we sold 30 drilling rigs, some old top drive equipment, and drill pipe in an auction. The proceeds from the sale of those assets, less costs to sell, was less than the $11.0 million net book value resulting in a loss of $7.3 million pre-tax.

During December 2016, we sold one idle 1500 HP SCR drilling rig to an unaffiliated third party. The proceeds of this sale, less costs to sell, exceeded the $1.7 million net book value of the drilling rig, resulting in a gain of $1.6 million.