Other Accrued Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Payables and Accruals [Abstract]
Royalties	$ 53,343	$ 74,061
Transportation Charges	19,556	16,533
Accrued Interest	16,896	30,862
Accrued Other Taxes	9,681	9,115
Deferred Revenue	8,934	13,964
Short-Term Incentive Compensation	7,785	21,030
Accrued Payroll & Benefits	6,082	6,248
Other	35,471	37,610
Current Portion of Long-Term Liabilities:
Asset Retirement Obligations	5,076	5,076
Salary Retirement	1,649	1,587
Total Other Accrued Liabilities	$ 164,473	$ 216,086

Accrued Transportation Charges

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Carrying value as of the balance sheet date of obligations incurred and payable for real and property taxes. 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 obligations incurred and payable for incentive compensation awarded to employees and directors or earned by them based on the terms of one or more relevant arrangements. 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 obligations incurred through that date and payable for royalties.

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Current portion of the carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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Amount of liability, recognized in statement of financial position, for defined benefit pension plan, classified as current. Excludes other postretirement benefit plan.

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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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