Partners' Equity, Income Allocations and Cash Distributions - Cash Distributions (Details) - USD ($) $ in Millions			3 Months Ended
	May 14, 2020	May 04, 2020	Mar. 31, 2020	Mar. 31, 2019
Incentive Distribution Made to Managing Member or General Partner [Line Items]
Document Period End Date			Mar. 31, 2020
Partners' Capital Account, Units			59,630,030
Ownership percentage, controlling interest			57.00%
Common Unit Issuance Program			$ 200.0
Partners' capital account, units, sale of units (in shares)			2,413,153
Limited partner distribution			$ 2.5
Gross proceeds from issuance of common units			82.3
Distributions declared			$ 34.5	$ 68.2
Subsequent Event
Incentive Distribution Made to Managing Member or General Partner [Line Items]
Dividends Payable, Date to be Paid	May 14, 2020
Dividends Payable, Date of Record		May 04, 2020