LONG-TERM DEBT - Exit Credit Facility (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	May 14, 2019	Dec. 31, 2018
Exit Credit Facility
Period the projected production volumes must be hedged	18 months
Revolving Credit Facility
Exit Credit Facility
Debt instrument ratio current consolidated assets to current consolidated liabilities	1.0
Debt instrument covenant percentage related to projected production volumes	70.00%
Maximum amount of cash that may be held per covenant, as a percent of borrowing base	5.00%
Maximum amount of cash that may be held if more than the specified percentage of borrowing base	$ 30.0
Debt instrument, covenant compliance	As of March 31, 2019, the Company was in compliance with all of these financial covenants
Revolving Credit Facility | Secured Debt
Exit Credit Facility
Credit facility, maximum borrowing capacity	$ 1,000.0
Credit facility expiration date	Feb. 26, 2021
Weighted average effective interest rate	5.00%		5.10%
Reduction in borrowing base	$ 2.0
Line of credit, borrowing base	260.3
Standby Letters of Credit
Exit Credit Facility
Credit facility, maximum borrowing capacity	50.0
Letter of credit outstanding	$ 0.2
Minimum | Revolving Credit Facility
Exit Credit Facility
Debt instrument covenant percentage of total value of mortgaged properties evaluated in reserve report	95.00%
Maximum | Revolving Credit Facility
Exit Credit Facility
Total debt to earnings ratio required under credit facility	4.0
Borrowing Base Determination, Period One | Revolving Credit Facility
Exit Credit Facility
Borrowing base scheduled redetermination date	--04-01
Borrowing Base Determination, Period Two | Revolving Credit Facility
Exit Credit Facility
Borrowing base scheduled redetermination date	--10-01
Subsequent Event
Exit Credit Facility
Credit facility, maximum borrowing capacity		$ 110.0
Subsequent Event | Revolving Credit Facility
Exit Credit Facility
Reduction in borrowing base		$ 150.3