Employee Retirement Plans (Fair values of pension plans' assets and VEBA trust assets) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2010
Pension Benefits [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	$ 351,543	$ 289,764	$ 287,902
Pension Benefits [Member] | Domestic [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	188,243	143,119
Pension Benefits [Member] | International [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	36,908	31,030
Pension Benefits [Member] | Fixed income [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	123,332	113,592
Pension Benefits [Member] | Cash equivalents [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	3,060	2,023
Pension Benefits [Member] | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	348,483	287,741
Pension Benefits [Member] | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Domestic [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	188,243	143,119
Pension Benefits [Member] | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | International [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	36,908	31,030
Pension Benefits [Member] | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Fixed income [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	123,332	113,592
Pension Benefits [Member] | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Cash equivalents [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
Pension Benefits [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	3,060	2,023
Pension Benefits [Member] | Significant Other Observable Inputs (Level 2) [Member] | Domestic [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
Pension Benefits [Member] | Significant Other Observable Inputs (Level 2) [Member] | International [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
Pension Benefits [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fixed income [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
Pension Benefits [Member] | Significant Other Observable Inputs (Level 2) [Member] | Cash equivalents [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	3,060	2,023
Pension Benefits [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
Pension Benefits [Member] | Unobservable Inputs (Level 3) [Member] | Domestic [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
Pension Benefits [Member] | Unobservable Inputs (Level 3) [Member] | International [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
Pension Benefits [Member] | Unobservable Inputs (Level 3) [Member] | Fixed income [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
Pension Benefits [Member] | Unobservable Inputs (Level 3) [Member] | Cash equivalents [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
VEBA Trust [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	11,205	9,806
VEBA Trust [Member] | Domestic [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	7,678	6,098
VEBA Trust [Member] | Fixed income [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	3,366	3,320
VEBA Trust [Member] | Cash equivalents [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	161	388
VEBA Trust [Member] | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	11,044	9,418
VEBA Trust [Member] | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Domestic [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	7,678	6,098
VEBA Trust [Member] | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Fixed income [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	3,366	3,320
VEBA Trust [Member] | Quoted Prices in Active Markets for Identical Assets and Liabilities (Level 1) [Member] | Cash equivalents [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
VEBA Trust [Member] | Significant Other Observable Inputs (Level 2) [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	161	388
VEBA Trust [Member] | Significant Other Observable Inputs (Level 2) [Member] | Domestic [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
VEBA Trust [Member] | Significant Other Observable Inputs (Level 2) [Member] | Fixed income [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
VEBA Trust [Member] | Significant Other Observable Inputs (Level 2) [Member] | Cash equivalents [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	161	388
VEBA Trust [Member] | Unobservable Inputs (Level 3) [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
VEBA Trust [Member] | Unobservable Inputs (Level 3) [Member] | Domestic [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
VEBA Trust [Member] | Unobservable Inputs (Level 3) [Member] | Fixed income [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	0	0
VEBA Trust [Member] | Unobservable Inputs (Level 3) [Member] | Cash equivalents [Member]
Fair Value of Pension Plan Assets
Fair Value of Plan Assets	$ 0	$ 0