OTHER SUPPLEMENTAL INFORMATION (Supplemental Cash Flows and Non-Cash Transactions) (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012
Supplemental cash flows information:
Cash paid for interest	$ 24,347	$ 26,778
Cash paid for income taxes	325	340
Non-cash transactions:
Costs for additions to oil and natural gas properties in accounts payable and accrued liabilities	16,636	7,153
Capitalized interest	$ 4,970

Future cash outflow to pay for purchases of fixed assets that have occurred.

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