Retirement and Post-Retirement Employee Benefit Plans Fair Value Disclosures (Details) (USD $)	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Schedule of Total Investments at Fair Value [Line Items]
Available-for-sale Securities	$ 79,613,000	$ 72,682,000
Fair Value Inputs Level 1 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Available-for-sale Securities	44,014,000	40,094,000
Fair Value Inputs Level 2 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Available-for-sale Securities	35,599,000	32,588,000
Fair Value Inputs Level 3 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Available-for-sale Securities	0	0
Pension Plans, Defined Benefit [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	432,109,000	396,482,000
Fair value of accounts receivable	2,700,000	400,000
Pension Plans, Defined Benefit [Member] | Equity Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	155,107,000	143,543,000
Pension Plans, Defined Benefit [Member] | Money Market Funds [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	11,226,000	12,266,000
Pension Plans, Defined Benefit [Member] | Registered Investment Companies, Domestic [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	63,850,000	30,200,000
Pension Plans, Defined Benefit [Member] | Registered Investment Companies, International [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	48,134,000	47,036,000
Pension Plans, Defined Benefit [Member] | Common Collective Trusts [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	61,208,000	57,627,000
Pension Plans, Defined Benefit [Member] | Mortgage-backed securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	12,520,000	18,446,000
Pension Plans, Defined Benefit [Member] | U.S. Treasuries [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	3,679,000	4,780,000
Pension Plans, Defined Benefit [Member] | Corporate Debt Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	25,734,000	35,012,000
Pension Plans, Defined Benefit [Member] | Limited Partnership Interest [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	50,496,000	47,417,000
Pension Plans, Defined Benefit [Member] | Real Estate Investment [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	155,000	155,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	270,208,000	224,896,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	155,107,000	143,543,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Money Market Funds [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Registered Investment Companies, Domestic [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	63,850,000	30,200,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Registered Investment Companies, International [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	48,134,000	47,036,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Common Collective Trusts [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Mortgage-backed securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | U.S. Treasuries [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	3,117,000	4,117,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Corporate Debt Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Limited Partnership Interest [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Real Estate Investment [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	161,746,000	171,431,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Money Market Funds [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	11,226,000	12,266,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Registered Investment Companies, Domestic [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Registered Investment Companies, International [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Common Collective Trusts [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	61,208,000	57,627,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Mortgage-backed securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	12,520,000	18,446,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | U.S. Treasuries [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	562,000	663,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Corporate Debt Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	25,734,000	35,012,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Limited Partnership Interest [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	50,496,000	47,417,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Real Estate Investment [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	155,000	155,000
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Equity Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Money Market Funds [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Registered Investment Companies, Domestic [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Registered Investment Companies, International [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Common Collective Trusts [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Mortgage-backed securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | U.S. Treasuries [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Corporate Debt Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Limited Partnership Interest [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Pension Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Real Estate Investment [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	155,000	155,000
Defined Benefit Plan, Plan Assets at Fair Value, Valuation Inputs	The fair value of our Level 3 real estate assets was determined using a real estate appraisal obtained from an independent third party that consisted of several unobservable inputs such as comparable land sales values per square foot in the range of $0.94 to $2.98 and comparable building sales values per square foot in the range of $23.13 to $30.42.
Other Postretirement Benefit Plans, Defined Benefit [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	134,821,000	106,413,000
Other Postretirement Benefit Plans, Defined Benefit [Member] | Money Market Funds [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	434,000	3,356,000
Other Postretirement Benefit Plans, Defined Benefit [Member] | Registered Investment Companies, Domestic [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	11,398,000	9,614,000
Other Postretirement Benefit Plans, Defined Benefit [Member] | Registered Investment Companies, International [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	122,989,000	93,443,000
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	134,387,000	103,057,000
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Money Market Funds [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Registered Investment Companies, Domestic [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	11,398,000	9,614,000
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Registered Investment Companies, International [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	122,989,000	93,443,000
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	434,000	3,356,000
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Money Market Funds [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	434,000	3,356,000
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Registered Investment Companies, Domestic [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Registered Investment Companies, International [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Money Market Funds [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Registered Investment Companies, Domestic [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Other Postretirement Benefit Plans, Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Registered Investment Companies, International [Member]
Schedule of Total Investments at Fair Value [Line Items]
Investments, Fair Value Disclosure	0	0
Supplemental Executive Retirement Plans, Defined Benefit [Member]
Schedule of Total Investments at Fair Value [Line Items]
Available-for-sale Securities	$ 46,200,000	$ 44,500,000
Minimum [Member]
Schedule of Total Investments at Fair Value [Line Items]
Comparable Land Sale Values	0.94
Comparable Building Sales Values	23.13
Maximum [Member]
Schedule of Total Investments at Fair Value [Line Items]
Comparable Land Sale Values	2.98
Comparable Building Sales Values	30.42