Long-Term Incentive Plan - Unit-based (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Long-Term Incentive Plan
Number of common units initially authorized for issuance under LTIP (in shares)	4,300,000		4,300,000
Weighted Average Grant Date Fair Value
Compensation expenses	$ 300	$ 800	$ 600	$ 1,600
Unrecognized compensation cost related to the non-vested awards	$ 2,100		$ 2,100
Repurchase Program
Aggregate common units authorized to be acquired (in shares)	1,242,427		1,242,427
Common units repurchased to date (in shares)	868,505		868,505
Common units repurchased to date, value	$ 25,100		$ 25,100
Common units repurchased during the period	291		300
Performance costs paid	$ 0	$ 0	$ 300	$ 300
Phantom Unit Awards [Member]
Number of Non-vested Units
Outstanding non-vested units at the beginning of the period (in shares)			562,906
Vested (in shares)			(5,129)
Forfeited (in shares)			(2,090)
Outstanding non-vested units at the end of the period (in shares)	555,687		555,687
Weighted Average Grant Date Fair Value
Outstanding non-vested units at the beginning of the period (in dollars per share)			$ 9.74
Vested (in dollars per share)			25.84
Forfeited (in dollars per share)			9.28
Outstanding non-vested units at the end of the period (in dollars per share)	$ 9.59		$ 9.59