Summary of Significant Accounting Policies - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2016 USD ($) counterparty	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Impairment	$ 4,684,000	$ 46,109,000	$ 47,238,000
Allowance for doubtful accounts		0
Capitalized interest costs	16,800,000	18,600,000	8,800,000
Amount of capitalized exploratory well costs that have been capitalized for period greater than one year	0
Decrease in long-term debt	$ (2,297,214,000)	(2,302,584,000)
Derivative, number of counterparties | counterparty	9
Past-due receivables from counterparties	$ 0
Restricted stock awards vesting period	3 years
Federal
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Stock-based compensation related to unrealized excess tax benefits	$ 10,600,000
State
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Stock-based compensation related to unrealized excess tax benefits	$ 8,600,000
1 to 12 months
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Contractual commodity derivative volume, percent	110.00%
13 to 24 months
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Contractual commodity derivative volume, percent	100.00%
25 to 36 months
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Contractual commodity derivative volume, percent	75.00%
37 to 60 months
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Contractual commodity derivative volume, percent	50.00%
Minimum
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Annual forfeiture rate	0.00%
Minimum | Performance share unit awards
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Annual forfeiture rate	3.30%
Maximum
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Annual forfeiture rate	20.00%
Maximum | Performance share unit awards
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Annual forfeiture rate	4.60%
Non-operated oil and natural gas properties
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Impairment	$ 3,600,000	9,400,000
Building
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Estimated life of assets	20 years
Proved oil and gas properties
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Impairment	$ 3,600,000			$ 0
Unproved oil and gas properties
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Impairment	$ 1,100,000	$ 36,600,000	$ 7,300,000
Salt water disposal facility
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Estimated life of assets	30 years
Furniture, software and equipment | Minimum
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Estimated life of assets	2 years
Furniture, software and equipment | Maximum
Interest Cost Capitalized And Depreciation And Amortization Expenses For Property, Plant and Equipment [Line Items]
Estimated life of assets	7 years