Carrying value as of the balance sheet date of obligations incurred and payable, pertaining to costs that are statutory in nature, are incurred on contractual obligations, or accumulate over time and for which invoices have not yet been received or will not be rendered. Examples include taxes, interest, rent and utilities. 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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Unrecognized cost of unvested share-based compensation awards.

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The noncash expense that represents the cost of restricted stock or unit distributed to employees as compensation.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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Amount of cash paid related to share-based compensation liabilities.

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The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

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Fair value of share-based awards for which the grantee gained the right by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Gross number of share options (or share units) granted during the period.

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Number of non-vested options outstanding.

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Value, before forfeitures, of stock or other type of equity granted of any equity-based compensation plan other than an employee stock ownership plan (ESOP).

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Number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP), net of any shares forfeited. Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

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Unit-Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
Unit-Based Compensation (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash settled restricted unit-based compensation awards	$ 147,444		$ 147,444		$ 187,687
Restricted units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common units, granted, aggregate value			$ 3,700	$ 1,600
Restricted units, granted (shares)			1,424,058	321,318
Vesting period from grant date			3 years
Non-vested restricted units outstanding (shares)	1,456,999		1,456,999		480,301
Common units, vested (shares)			342,560	255,370
Common units, vested, value			$ 2,000	$ 2,200
Stock issued during period (shares)			111,336	83,060
Amount paid to grantees in cash			$ 400	$ 600
Cash settled restricted unit-based compensation awards	$ 1,200		1,200		$ 500
Non-vested awards not yet recognized	2,800		$ 2,800
Expected weighted average period to recognition			9 months 18 days
Non-management directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common units, granted (shares)			293,770
Common units, granted, aggregate value			$ 800
General and administrative expenses \| Restricted units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based compensation expense	$ 300	$ 100	$ 1,700	$ 700