Fair Value Measurements Available-For-Sale Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Sep. 30, 2014
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 66,399	$ 67,466
Gross Unrealized Gain	8,343	12,160
Gross Unrealized Loss	(542)	(13)
Fair value	74,200	79,613
Available-for-sale Securities, Other Disclosure Items [Abstract]
Available-for-sale Securities, Supplemental Executive Benefit Plans	41,700	46,200
Equity Funds Domestic [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	27,643	26,633
Gross Unrealized Gain	7,332	10,136
Gross Unrealized Loss	(456)	0
Fair value	34,519	36,769
Equity Funds Foreign [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	5,261	5,382
Gross Unrealized Gain	905	1,863
Gross Unrealized Loss	(66)	0
Fair value	6,100	7,245
Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	32,423	33,266
Gross Unrealized Gain	106	161
Gross Unrealized Loss	(20)	(13)
Fair value	32,509	33,414
Money Market Funds [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,072	2,185
Gross Unrealized Gain	0	0
Gross Unrealized Loss	0	0
Fair value	$ 1,072	$ 2,185