CONDENSED CONSOLIDATED STATEMENT OF PARTNERS' CAPITAL - USD ($) shares in Thousands, $ in Thousands	Total	General Partner	Common Stock	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Sep. 30, 2019	$ 260,840	$ (1,968)	$ 279,709	$ (16,901)
Beginning Balance, unit at Sep. 30, 2019		326	47,685
Net income	27,755	$ 192	$ 27,563
Unrealized gain on pension plan obligation	455			455
Tax effect of unrealized gain on pension plan obligation	(125)			(125)
Unrealized loss on captive insurance collateral	(64)			(64)
Tax effect of unrealized loss on captive insurance collateral	8			8
Unrealized gain on interest rate hedges	334			334
Tax effect of unrealized gain on interest rate hedges	(86)			(86)
Distributions	(6,155)	(215)	(5,940)
Retirement of units	(12,064)		$ (12,064)
Retirement of units, shares			(1,281)
Ending Balance at Dec. 31, 2019	270,898	$ (1,991)	$ 289,268	(16,379)
Ending Balance, Unit at Dec. 31, 2019		326	46,404
Beginning Balance at Sep. 30, 2020	255,820	$ (2,506)	$ 273,283	(14,957)
Beginning Balance, unit at Sep. 30, 2020		326	43,328
Net income	37,860	$ 296	$ 37,564
Unrealized gain on pension plan obligation	235			235
Tax effect of unrealized gain on pension plan obligation	(64)			(64)
Unrealized loss on captive insurance collateral	(340)			(340)
Tax effect of unrealized loss on captive insurance collateral	72			72
Unrealized gain on interest rate hedges	332			332
Tax effect of unrealized gain on interest rate hedges	(88)			(88)
Distributions	(5,939)	(237)	(5,702)
Retirement of units	(25,272)		$ (25,272)
Retirement of units, shares			(2,591)
Ending Balance at Dec. 31, 2020	$ 262,616	$ (2,447)	$ 279,873	$ (14,810)
Ending Balance, Unit at Dec. 31, 2020		326	40,737