Income Taxes Income Taxes (Schedule of Deferred Tax Assets and Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Income Tax Disclosure [Abstract]
Net operating loss carryforward	$ 1,091	$ 1,462	$ 1,513
FASB ASC 718 compensation expense	1,562	634	762
AMT credit	24,053	7,968	1,643
Charitable contributions carryover	150	25	5
Unrealized loss on hedging activities	0	8,540	3,836
Foreign tax credit carryforwards	2,074	2,074	2,074
Accrued liabilities	1,260	0	0
State net operating loss carryover	2,627	4,408	4,315
Total deferred tax assets	32,817us-gaap_DeferredTaxAssetsGross	25,111us-gaap_DeferredTaxAssetsGross	14,148us-gaap_DeferredTaxAssetsGross
Valuation allowance for deferred tax assets	(3,145)	(4,743)	(4,629)
Deferred tax assets, net of valuation allowance	29,672us-gaap_DeferredTaxAssetsNet	20,368us-gaap_DeferredTaxAssetsNet	9,519us-gaap_DeferredTaxAssetsNet
Oil and gas property basis difference	183,767	72,173	15,049
Investment in pass through entities	38,315	8,799	3,618
Non-oil and gas property basis difference	849	249	227
Investment in nonconsolidated affiliates	0	46,495	9,232
Unrealized gain on hedging activities	37,006	0	0
Total deferred tax liabilities	259,937us-gaap_DeferredTaxLiabilities	127,716us-gaap_DeferredTaxLiabilities	28,126us-gaap_DeferredTaxLiabilities
Net deferred tax liability	$ (230,265)	$ (107,348)	$ (18,607)

Deferred Tax Liabilities, Non-oil And Gas Property Basis Difference

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The tax effect as of the balance sheet date of the estimated future tax effects attributable to the difference between the tax basis of oil and gas assets and the basis of oil and gas assets computed in accordance with generally accepted accounting principles. The difference in basis, attributable to different capitalization of costs, depreciation, or amortization methodologies, will impact future taxable income when such basis difference is realized.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible charitable contribution carryforwards.

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Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards, net of deferred tax liability attributable to taxable temporary differences expected to be realized or consumed after one year (or the normal operating cycle, if longer).

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible alternative minimum tax credit carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible foreign tax credit carryforwards.

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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences from share-based compensation.

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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.

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Amount of deferred tax liability attributable to taxable temporary differences from investments in unconsolidated subsidiaries and investments in other affiliates which are not controlled nor consolidated.

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