Accounts Receivable and Accounts Payable and Accrued Expenses Accounts Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable
Accounts Receivable, Net, Current	$ 151,950	$ 134,124
Accrued oil, gas, and NGL production revenue [Member]
Accounts, Notes, Loans and Financing Receivable
Accounts Receivable, Net, Current	96,101	58,256
Amounts due From Joint Interest Owners [Member]
Accounts, Notes, Loans and Financing Receivable
Accounts Receivable, Net, Current	29,669	22,269
State severance tax refunds [Member]
Accounts, Notes, Loans and Financing Receivable
Accounts Receivable, Net, Current	15,320	12,072
Accrued derivative settlements [Member]
Accounts, Notes, Loans and Financing Receivable
Accounts Receivable, Net, Current	6,512	34,579
Other [Member]
Accounts, Notes, Loans and Financing Receivable
Accounts Receivable, Net, Current	$ 4,348	$ 6,948