Accounts Receivable and Accounts Payable and Accrued Expenses Accounts Payable and Accrued Expenses (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Accounts Payable and Accrued Expenses
Capital Expenditures Incurred but Not yet Paid	$ 217,820	$ 262,800	$ 214,800
Accounts payable and accrued expenses	606,751	525,627
Accrued Drilling Costs
Accounts Payable and Accrued Expenses
Accounts payable and accrued expenses		243,611
Revenue and Severence Taxes Payable
Accounts Payable and Accrued Expenses
Accounts payable and accrued expenses	87,852	65,494
Accrued Lease Operating Expense
Accounts Payable and Accrued Expenses
Accounts payable and accrued expenses	29,296	28,037
Accrued property taxes
Accounts Payable and Accrued Expenses
Accounts payable and accrued expenses	10,401	9,478
Joint Owner Advances
Accounts Payable and Accrued Expenses
Accounts payable and accrued expenses	96,636	69,639
Accrued Compensation Costs
Accounts Payable and Accrued Expenses
Accounts payable and accrued expenses	71,466	35,607
Accrued interest
Accounts Payable and Accrued Expenses
Accounts payable and accrued expenses	40,027	25,027
Other
Accounts Payable and Accrued Expenses
Accounts payable and accrued expenses	$ 53,253	$ 48,734