Divestitures - Narrative (Details)	12 Months Ended
	Dec. 31, 2016 USD ($) rig	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) rig
Oil and Natural Gas [Member]
Divestiture [Line Items]
Proceeds from divestiture of assets	$ 67,200,000	$ 1,900,000	$ 33,100,000
Drilling Equipment
Divestiture [Line Items]
Number of rigs sold | rig	1		4
Net book value of drilling rigs sold	$ 1,700,000.0		$ 16,300,000.0
Gain (loss) on sale of drilling rigs	$ 1,600,000		$ 9,600,000