Consolidated Statements of Partners' Capital (USD $) In Thousands		Total	Common Stock	General Partner	Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Sep. 30, 2011		$ 272,633	$ 299,913	$ 187	$ (27,467)
Beginning Balance, unit at Sep. 30, 2011			64,970	326
Net income		25,989	25,853	136
Unrealized gain (loss) on pension plan obligation	[1]	1,176			1,176
Tax effect of unrealized gain (loss) on pension plan obligation		(480)			(480)
Distributions	[2]	(19,525)	(19,299)	(226)
Retirement of units, shares	[3]		(3,968)
Retirement of units	[3]	(19,648)	(19,648)
Ending Balance at Sep. 30, 2012		260,145	286,819	97	(26,771)
Ending Balance, Unit at Sep. 30, 2012			61,002	326
Net income		29,906	29,747	159
Unrealized gain (loss) on pension plan obligation	[1]	6,337			6,337
Tax effect of unrealized gain (loss) on pension plan obligation		(2,577)			(2,577)
Distributions	[2]	(19,313)	(19,060)	(253)
Retirement of units, shares	[3]		(3,284)
Retirement of units	[3]	(15,217)	(15,217)
Ending Balance at Sep. 30, 2013		259,281	282,289	3	(23,011)
Ending Balance, Unit at Sep. 30, 2013			57,718	326
Net income		36,084	35,881	203
Unrealized gain (loss) on pension plan obligation	[1]	(1,070)			(1,070)
Tax effect of unrealized gain (loss) on pension plan obligation		463			463
Distributions	[2]	(19,850)	(19,539)	(311)
Retirement of units, shares	[3]		(313)
Retirement of units	[3]	(1,663)	(1,663)
Ending Balance at Sep. 30, 2014		$ 273,245	$ 296,968	$ (105)	$ (23,618)
Ending Balance, Unit at Sep. 30, 2014			57,405	326

[1] These items are included in the computation of net periodic pension cost. See Note 12-Employee Benefit Plan.

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

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