Retirement and Post-Retirement Employee Benefit Plans Fair Value Disclosures (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011
Pension Plans Defined Benefit [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	$ 350,296	$ 279,759
Pension Plans Defined Benefit [Member] | Equity Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	114,799	94,336
Pension Plans Defined Benefit [Member] | Money Market Funds [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	21,010	9,383
Pension Plans Defined Benefit [Member] | Registered Investment Companies, Domestic [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	19,984	12,921
Pension Plans Defined Benefit [Member] | Registered Investment Companies, International [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	36,714	27,528
Pension Plans Defined Benefit [Member] | Common Collective Trusts [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	52,155	40,096
Pension Plans Defined Benefit [Member] | Mortgage-backed securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	19,509	18,860
Pension Plans Defined Benefit [Member] | U.S. Treasuries [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	8,084	4,993
Pension Plans Defined Benefit [Member] | Corporate Debt Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	35,960	33,636
Pension Plans Defined Benefit [Member] | Limited Partnership Interest [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	41,926	37,806
Pension Plans Defined Benefit [Member] | Real Estate Investment [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	155	200
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 1 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	179,234	139,844
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Equity Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	114,799	94,336
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Money Market Funds [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	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]
Total investments at fair value	19,984	12,921
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]
Total investments at fair value	36,714	27,528
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Common Collective Trusts [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	7,597	4,946
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Corporate Debt Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	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]
Total investments at fair value	140	113
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 1 [Member] | Real Estate Investment [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	0	0
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 2 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	170,907	139,715
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Equity Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	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]
Total investments at fair value	21,010	9,383
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]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	52,155	40,096
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Mortgage-backed securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	19,509	18,860
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | U.S. Treasuries [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	487	47
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Corporate Debt Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	35,960	33,636
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Limited Partnership Interest [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	41,786	37,693
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 2 [Member] | Real Estate Investment [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	0	0
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 3 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	155	200
Pension Plans Defined Benefit [Member] | Fair Value Inputs Level 3 [Member] | Equity Securities [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	155	200
Other Postretirement Benefit Plans Defined Benefit [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	78,568	53,065
Other Postretirement Benefit Plans Defined Benefit [Member] | Money Market Funds [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	2,360	1,707
Other Postretirement Benefit Plans Defined Benefit [Member] | Registered Investment Companies, Domestic [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	7,756	3,506
Other Postretirement Benefit Plans Defined Benefit [Member] | Registered Investment Companies, International [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	68,452	47,852
Other Postretirement Benefit Plans Defined Benefit [Member] | Fair Value Inputs Level 1 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	76,208	51,358
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]
Total investments at fair value	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]
Total investments at fair value	7,756	3,506
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]
Total investments at fair value	68,452	47,852
Other Postretirement Benefit Plans Defined Benefit [Member] | Fair Value Inputs Level 2 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	2,360	1,707
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]
Total investments at fair value	2,360	1,707
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]
Total investments at fair value	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]
Total investments at fair value	0	0
Other Postretirement Benefit Plans Defined Benefit [Member] | Fair Value Inputs Level 3 [Member]
Schedule of Total Investments at Fair Value [Line Items]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	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]
Total investments at fair value	$ 0	$ 0