Summary Of Significant Accounting Policies (Narrative) (Details)	3 Months Ended			12 Months Ended
	Sep. 30, 2015 USD ($) rig	Mar. 31, 2015 USD ($) rig	Dec. 31, 2014 USD ($) rig	Dec. 31, 2016 USD ($) contract Unit rig MMcf		Dec. 31, 2015 USD ($) rig systems	Dec. 31, 2014 USD ($) rig systems	Dec. 31, 2013 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of daywork contracts | contract				8
Number of contracts, daywork expiring in one year | contract				7
Number of contracts, daywork expiring in two years | contract				1
Book Overdrafts				$ 17,300,000		$ 22,100,000
Concentration of cash				8,300,000		$ 2,300,000
Impairment of gas gathering systems				0
Number of gas gathering systems impaired | systems						3	3
Interest Costs Capitalized				15,300,000		$ 21,700,000	$ 32,200,000
Additions to goodwill				0
Goodwill impairment				$ 0
Percentage fair value exceeds carrying value for goodwill				16.00%
Goodwill deductible for tax purposes				$ 1,300,000
Directly related overhead costs capitalized			$ 23,700,000	15,400,000		19,200,000	23,700,000
Average rates used for depreciation, depletion, and amortization per Boe				6.24		12.30	14.82
Unproved properties not being amortized			485,568,000	$ 314,867,000		337,099,000	485,568,000
Future discounted net cash flows discounted				10.00%
Unproved properties included in amortization			73,700,000	$ 7,600,000		114,400,000	73,700,000
Non-cash ceiling test write-down net of tax				100,600,000		1,000,000,000	47,700,000
Revenues from transactions with operating segments of same entity				0		22,100,000	89,500,000
Eliminated associated operating expense				0		18,300,000	62,400,000
Eliminated yielding				$ 0		3,800,000	27,100,000
Number of oil and gas limited partnerships | Unit				13
Unrecognized tax benefits			$ 410,000	$ 410,000		$ 410,000	410,000	$ 0
Minimum
Summary Of Significant Accounting Policies [Line Items]
Number of days for drilling of one well				10 days
Duration length of contracts				6 months
Insurance coverage				$ 0
Maximum
Summary Of Significant Accounting Policies [Line Items]
Number of days for drilling of one well				90 days
Duration length of contracts				2 years
Insurance coverage				$ 1,000,000
Under-Produced Properties
Summary Of Significant Accounting Policies [Line Items]
Natural gas balancing (MMcf) | MMcf				3,700
Over-Produced Properties
Summary Of Significant Accounting Policies [Line Items]
Natural gas balancing (MMcf) | MMcf				3,300
Natural Gas Balancing
Summary Of Significant Accounting Policies [Line Items]
Accounts receivable				$ 2,800,000
Liability recognized to under production				$ 3,800,000
Drilling Equipment
Summary Of Significant Accounting Policies [Line Items]
Minimum depreciation percentage for idle drilling rigs				20.00%
Number of drilling rigs removed from service | rig						30
Drilling Equipment | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life, years				15 years
Property, Plant and Equipment, Other Types | Minimum
Summary Of Significant Accounting Policies [Line Items]
Useful life, years				3 years
Property, Plant and Equipment, Other Types | Maximum
Summary Of Significant Accounting Policies [Line Items]
Useful life, years				15 years
Drilling [Member]
Summary Of Significant Accounting Policies [Line Items]
Number of drilling rigs removed from service | rig			31
Impairment of contract drilling equipment				$ 0	[1]	$ 8,314,000	74,318,000
Number of rigs sold | rig	30	1
Net book value of drilling rigs sold	$ 11,000,000.0	$ 300,000.0
Gain (loss) on sale of drilling rigs	$ (7,300,000)	$ 7,900
Mid-Stream [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment of gas gathering systems				0	[1]	26,966,000	7,068,000
Oil and Natural Gas [Member]
Summary Of Significant Accounting Policies [Line Items]
Impairment of oil and natural gas properties				$ 161,563,000		$ 1,599,348,000	$ 76,683,000
Drilling Equipment
Summary Of Significant Accounting Policies [Line Items]
Number of rigs sold | rig				1			4
Net book value of drilling rigs sold			$ 16,300,000.0	$ 1,700,000.0			$ 16,300,000.0
Gain (loss) on sale of drilling rigs				$ 1,600,000			$ 9,600,000

[1] We incurred non-cash ceiling test write-down of our oil and natural gas properties of $161.6 million pre-tax ($100.6 million, net of tax).