CONSOLIDATED STATEMENTS OF PARTNERS' CAPITAL - USD ($) shares in Thousands, $ in Thousands		Total	General Partner	Common Stock	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Sep. 30, 2015		$ 289,886	$ (283)	$ 312,713	$ (22,544)
Beginning Balance, unit at Sep. 30, 2015			326	57,283
Net income		44,934	$ 252	$ 44,682
Unrealized gain (loss) on pension plan obligation	[1]	3,067			3,067
Tax effect of unrealized gain (loss) on pension plan obligation		(1,285)			(1,285)
Distributions	[2]	(23,092)	(485)	(22,607)
Retirement of units	[3]	(12,017)		$ (12,017)
Retirement of units, shares	[3]			(1,395)
Ending Balance at Sep. 30, 2016		301,493	$ (516)	$ 322,771	(20,762)
Ending Balance, Unit at Sep. 30, 2016			326	55,888
Net income		26,900	$ 156	$ 26,744
Unrealized gain (loss) on pension plan obligation	[1]	3,356			3,356
Tax effect of unrealized gain (loss) on pension plan obligation		(1,359)			(1,359)
Distributions	[2]	(24,322)	(569)	(23,753)
Ending Balance at Sep. 30, 2017		306,068	$ (929)	$ 325,762	(18,765)
Ending Balance, Unit at Sep. 30, 2017			326	55,888
Reclassification of stranded tax effects resulting from tax reform				$ (195)	195
Net income		55,505	$ 314	55,191
Unrealized gain (loss) on pension plan obligation	[1]	2,075			2,075
Tax effect of unrealized gain (loss) on pension plan obligation		(625)			(625)
Unrealized loss on captive insurance collateral		(1,204)			(1,204)
Tax effect of unrealized loss on captive insurance collateral		254			254
Unrealized gain on interest rate hedge		39			39
Tax effect of unrealized gain on interest rate hedge		(10)			(10)
Distributions	[2]	(25,603)	(688)	(24,915)
Retirement of units	[3]	(26,714)		$ (26,714)
Retirement of units, shares	[3]			(2,800)
Ending Balance at Sep. 30, 2018		$ 309,785	$ (1,303)	$ 329,129	$ (18,041)
Ending Balance, Unit at Sep. 30, 2018			326	53,088

[1] These items are included in the computation of net periodic pension cost. See Note 13 - Employee Benefit Plans.

[2] See Note 3 - Quarterly Distributions of Available Cash.

[3] See Note 4 - Common Unit Repurchase Plans and Retirement.