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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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Unit Based Compensation (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
Unit Based Compensation (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash settled restricted unit-based compensation awards	$ 142,147		$ 142,147		$ 187,687
Restricted Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common units aggregate value, granted			$ 3,700	$ 1,600
Restricted units, granted (in units)			1,424,058	321,318
Vesting period from grant date			3 years
Non vested restricted units outstanding (in units)	1,502,923		1,502,923		480,301
Common units, vested (in units)			342,560	255,370
Common units, value			$ 2,000	$ 2,200
Stock issued during period, shares, share-based compensation, net of forfeitures (in units)			111,336	83,060
Amount paid to grantees in cash			$ 400	$ 600
Cash settled restricted unit-based compensation awards	$ 1,000		1,000		$ 500
Non-vested awards not yet recognized	3,500		$ 3,500
Expected weighted average period of non-vested awards not yet recognized			1 year
Non-Management Directors
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common units, granted (in units)			293,770
Common units aggregate value, granted			$ 800
General and Administrative Expense [Member] \| Restricted Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Restricted stock or unit expense	$ (600)	$ 100	$ (1,400)	$ (600)