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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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

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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	1 Months Ended			12 Months Ended
Unit Based Compensation (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Unit-based compensation expense				$ 62,249	$ 56,122	$ 72,613
Cash settled restricted unit-based compensation awards				$ 187,687	$ 150,281
Restricted Unit
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common units aggregate value, granted	$ 1,600	$ 2,400	$ 2,100
Restricted units granted	321,318	601,368	102,834
Vesting period from grant date (in years)				3 years
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares				480,301	361,355	87,534
Common units, vested				255,370	76,637	48,488
Common units, value				$ 2,200	$ 2,000	$ 1,500
Equity based compensation and other, units				83,060	25,286	12,612
Payment to the grantees				$ 600	$ 200	$ 500
Unit-based compensation expense				900	1,900	$ 900
Cash settled restricted unit-based compensation awards				500	$ 1,100
Non-vested awards not yet recognized				$ 1,100
Expected weighted average period of non-vested awards not yet recognized (in years)				8 months 12 days
Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options granted (in units)				56,950
Common units aggregate value, granted				$ 300