Long-Term Debt Senior Notes (Details)	1 Months Ended	12 Months Ended
	Mar. 31, 2011 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Aug. 31, 2016 USD ($)	Oct. 31, 2013 USD ($)	Apr. 30, 2011 USD ($)
Debt Instrument [Line Items]
Loss on early extinguishment of long-term debt		$ 3,967,000	$ 0	$ 0
7.75% Senior Notes due 2019
Debt Instrument [Line Items]
Debt instrument, face amount	$ 300,000,000					$ 250,000,000	$ 50,000,000
Interest rate percentage		7.75%	7.75%
Debt instrument, repurchased face amount					$ 100,000,000
Original issue discount (as a percent)							1.00%
Unamortized original issue discount		$ 144,000	$ 241,000				$ 500,000
Discount on debt extinguishment		5,000,000
Write off of deferred debt issuance cost		$ 1,000,000
Minimum ratio of EBITDAX to consolidated interest expense	2.25
Current borrowing capacity	$ 500,000,000
Percent of net assets	0.3
7.75% Senior Notes due 2019 | Redemption Period Beginning April 2017
Debt Instrument [Line Items]
Redemption price of debt instrument (as a percent)		100.00%