Accrued Liabilities (Accrued Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Accounts Payable and Accrued Liabilities, Current [Abstract]
Interest payable	$ 17,260	$ 6,504
Employee costs	15,797	27,633
Lease operating expenses	15,696	16,073
Taxes	5,432	2,313
Derivative settlements	1,370	416
Deposits on assets held for sale	0	3,750
Other	9,670	7,674
Total accrued liabilities	$ 65,225	$ 64,363

Carrying value as of the balance sheet date of obligations, excluding pension and other postretirement benefits, incurred through that date and payable for perquisites provided to employees pertaining to services received from them. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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- Definition

Carrying value as of the balance sheet date of obligations incurred through that date and payable arising from transactions not otherwise specified in the taxonomy. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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