Net Income Per Limited Partner Unit - Schedule of Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions			3 Months Ended		6 Months Ended
	Aug. 14, 2019	May 15, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Partner distributions declared	$ 34,400	$ 33,000	$ 37,600	$ 34,400	$ 75,200	$ 67,400
Net income attributable to the Partnership in excess of distributions			3,000	2,900	7,100	7,100
Net income attributable to the Partnership			$ 40,600	$ 37,300	$ 82,300	$ 74,500
Weighted average units outstanding:
Basic and Diluted (in shares)			104.8	104.8	104.8	104.8
Incentive distribution rights currently held by the General Partner
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Partner distributions declared	400	200	$ 1,200	$ 400	$ 2,400	$ 600
Net income attributable to the Partnership in excess of distributions			0	0	0	0
Net income attributable to the Partnership			1,200	400	2,400	600
Limited partners' distribution declared on common units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Partner distributions declared	17,000	16,400	18,200	17,000	36,400	33,400
Net income attributable to the Partnership in excess of distributions			1,500	1,500	3,600	3,600
Net income attributable to the Partnership			$ 19,700	$ 18,500	$ 40,000	$ 37,000
Weighted average units outstanding:
Basic and Diluted (in shares)			52.4	52.4	52.4	52.4
Net income per limited partner unit (in dollars):
Basic and Diluted (in dollars per share)			$ 0.38	$ 0.35	$ 0.77	$ 0.70
Limited partners' distribution declared on subordinated units
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Partner distributions declared	$ 17,000	$ 16,400	$ 18,200	$ 17,000	$ 36,400	$ 33,400
Net income attributable to the Partnership in excess of distributions			1,500	1,400	3,500	3,500
Net income attributable to the Partnership			$ 19,700	$ 18,400	$ 39,900	$ 36,900
Weighted average units outstanding:
Basic and Diluted (in shares)			52.4	52.4	52.4	52.4
Net income per limited partner unit (in dollars):
Basic and Diluted (in dollars per share)			$ 0.38	$ 0.35	$ 0.77	$ 0.70