Condensed Consolidated Statements of Changes in Partners' Capital (Deficit) (Unaudited) (Parentheticals) - shares shares in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Limited Partner [Member]
Common units issued pursuant to the Employee Unit Purchase Plan (in shares)	98,631	40,081	161,971	61,327

Number of shares issued during the period as a result of an employee stock purchase plan.

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Name:	us-gaap_StockIssuedDuringPeriodSharesEmployeeStockPurchasePlans
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration