Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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-Publisher FASB
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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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The difference between the maximum number of shares (or other type of equity) authorized for issuance under the plan (including the effects of amendments and adjustments), and the sum of: 1) the number of shares (or other type of equity) already issued upon exercise of options or other equity-based awards under the plan; and 2) shares (or other type of equity) reserved for issuance on granting of outstanding awards, net of cancellations and forfeitures, if applicable.

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Price of a single share of a number of saleable stocks of a company.

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Partners' Capital, Conversion Factor, Conversion Ratio

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Number of annual vesting periods for which units are vested equally.

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SUBSEQUENT EVENTS - Long-term Incentive Plan (Details) $ / shares in Units, $ in Thousands	1 Months Ended		12 Months Ended
	Mar. 13, 2018 USD ($) $ / shares shares	Feb. 28, 2018 installment shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($) shares	Nov. 16, 2017 shares	Dec. 31, 2014 shares
Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)			4 years
Director \| Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)			1 year
Long-Term Incentive Plan \| Phantom Share Units (PSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Conversion ratio			1
Common units authorized for issuance (in shares)						3,654,167	1,654,167
Maximum number of common units available for issuance (in shares)			2,189,688
Long-Term Incentive Plan \| Phantom Share Units (PSUs) \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested in period (in units)	369,903
Common units authorized for issuance (in shares)		546,940
Maximum number of common units available for issuance (in shares)	1,797,127
Number of vesting periods \| installment		4
Long-Term Incentive Plan \| Common units \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted in period (in units)	244,794
Cash Paid \| $	$ 96
Long-Term Incentive Plan \| Liability Classified
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Cash Paid \| $			$ 65	$ 56	$ 24
Long-Term Incentive Plan \| Liability Classified \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares price (dollars per share) \| $ / shares	$ 11.55
Long-Term Incentive Plan \| Director and independent consultants \| Liability Classified
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested in period (in units)			21,610	10,256	0
Granted in period (in units)			8,333	21,610	10,256
Long-Term Incentive Plan \| Employee \| Liability Classified
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested in period (in units)			13,633	8,682	4,426
Granted in period (in units)			19,812	17,021	17,702
Long-Term Incentive Plan \| Director \| Phantom Share Units (PSUs) \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award vesting period (in years)		1 year
U.S. \| Long-Term Incentive Plan \| Director and independent consultants \| Phantom Share Units (PSUs) \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested in period (in units)	24,999
Conversion ratio	1
U.S. \| Long-Term Incentive Plan \| Director and independent consultants \| Common units \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted in period (in units)	24,999
Cash Paid \| $	$ 0
U.S. \| Long-Term Incentive Plan \| Employee \| Phantom Share Units (PSUs) \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested in period (in units)	336,571
U.S. \| Long-Term Incentive Plan \| Employee \| Common units \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted in period (in units)	219,795
Cash Paid \| $	$ 0
Canada \| Long-Term Incentive Plan \| Director and independent consultants \| Phantom Share Units (PSUs) \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vested in period (in units)	8,333
Canada \| Long-Term Incentive Plan \| Director and independent consultants \| Common units \| Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted in period (in units)	0
Cash Paid \| $	$ 96