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Debt (Details) - Business Acquisition, Acquiree [Domain] - Credit Facility [Domain] $ in Thousands | 1 Months Ended | 12 Months Ended |  |
--- | --- | --- | --- | ---
Jul. 31, 2010 USD ($) | Sep. 30, 2014 USD ($) item | Sep. 30, 2013 USD ($) | Sep. 30, 2012 USD ($) | Jan. 31, 2014 USD ($) | Jun. 30, 2013 USD ($)
Debt |  |  |  |  |  |
Total debt |  | $ 1,004,000 | $ 1,173,300 |  |  |
Less: Current portion of debt and short-term borrowings |  | (64,400) | (84,300) |  |  |
Long-term debt, less current portion |  | 939,565 | 1,089,060 |  |  |
Scheduled maturities of debt: |  |  |  |  |  |
2016 |  | 38,000 |  |  |  |
2017 |  | 37,700 |  |  |  |
2018 |  | 600,000 |  |  |  |
Thereafter |  | 263,900 |  |  |  |
Total debt |  | 1,004,000 | 1,173,300 |  |  |
2015 |  | 64,400 |  |  |  |
Debt agreements |  |  |  |  |  |
Repayment of indebtedness |  | $ 1,998,882 | 2,156,399 | $ 1,550,996 |  |
Interest rate, basis spread (as a percent) |  | 0.125% |  |  |  |
Senior notes assumed in acquisition as part of consideration |  | $ 18,300 | 5,600 |  |  |
Debt |  | $ 1,004,000 | 1,173,300 |  |  |
Contingent increase to maximum borrowing capacity under the credit facility |  |  |  |  | $ 1,250,000 |
Actual consolidated leverage ratio |  | 2.55 |  |  |  |
Maximum consolidated leverage ratio |  | 3.0 |  |  |  |
Actual net worth of the entity |  | $ 2,186,517 | $ 2,021,443 |  |  |
Average effective interest rate on total borrowings, including the effects of swaps (as a percent) |  | 2.80% | 3.00% | 3.10% |  |
Parent |  |  |  |  |  |
Debt |  |  |  |  |  |
Long-term debt, less current portion |  | $ 938,900 | $ 1,087,400 |  |  |
Debt agreements |  |  |  |  |  |
Repayment of indebtedness |  | 1,918,600 | 2,145,700 | $ 1,513,600 |  |
Actual net worth of the entity |  | $ 2,178,500 | $ 2,009,400 |  |  |
Notes Payable to Banks | Minimum |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Number of subsidiary guarantors | item |  | 1 |  |  |  |
Notes Payable to Banks June 2013 Agreement [Member] |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Principal amount |  |  |  |  |  | $ 750,000
Additional borrowings available |  |  |  |  |  | 100,000
Average interest rate (as a percent) |  | 1.66% |  |  |  |
Final principal payment |  | $ 600,000 |  |  |  |
Notes Payable to Banks June 2013 Agreement [Member] | Base Rate [Member] |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Description of interest rate basis |  | Base Rate |  |  |  |
Notes Payable to Banks June 2013 Agreement [Member] | Base Rate [Member] | Maximum |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Interest rate, basis spread (as a percent) |  | 1.25% |  |  |  |
Notes Payable to Banks June 2013 Agreement [Member] | Debt Instrument Variable Rate Base Eurocurrency Rate |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Description of interest rate basis |  | Eurodollar Rate |  |  |  |
Notes Payable to Banks June 2013 Agreement [Member] | Debt Instrument Variable Rate Base Eurocurrency Rate | Maximum |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Interest rate, basis spread (as a percent) |  | 2.25% |  |  |  |
Notes Payable to Banks June 2013 Agreement [Member] | Debt Instrument Variable Rate Base Eurocurrency Rate | Minimum |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Interest rate, basis spread (as a percent) |  | 1.125% |  |  |  |
Notes Payable to Banks September 2011 Agreement [Member] |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Repayment of indebtedness |  | $ 675,000 |  |  |  |
Average interest rate (as a percent) |  |  | 1.98% |  |  |
Senior Notes |  |  |  |  |  |
Debt |  |  |  |  |  |
Total debt |  | 263,900 | $ 260,200 |  |  |
Scheduled maturities of debt: |  |  |  |  |  |
Total debt |  | 263,900 | 260,200 |  |  |
Debt agreements |  |  |  |  |  |
Principal amount | $ 300,000 |  |  |  |  |
Debt |  | 263,900 | 260,200 |  |  |
Fair value of debt instrument |  | 287,400 | 269,400 |  |  |
Proceeds from sale of senior notes | 249,800 |  |  |  |  |
Net worth threshold, base amount |  |  |  |  |  | $ 1,200,000
Net worth threshold, percentage of the consolidated net income for each fiscal quarter commencing with the specified period |  |  |  |  |  | 40.00%
Actual net worth of the entity |  | 2,200,000 |  |  |  |
Net worth threshold |  | $ 1,700,000 |  |  |  |
Senior Notes | Minimum |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Number of subsidiary guarantors | item |  | 1 |  |  |  |
Senior Notes 5.00 Percent Due 2022 |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Principal amount |  | $ 800,000 |  |  |  |
Interest rate (as a percent) |  | 5.75% |  |  |  |
Senior Notes 5.43 Percent Series A Due July 2020 |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Principal amount | $ 175,000 |  |  |  |  |
Interest rate (as a percent) | 5.43% |  |  |  |  |
Senior Discount Notes 1.00 Percent Series B Due July 2022 |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Principal amount | $ 125,000 |  |  |  |  |
Interest rate (as a percent) | 1.00% |  |  |  |  |
Effective interest rate (as a percent) |  | 5.62% |  |  |  |
Total debt |  | $ 88,900 | 85,200 |  |  |
Other Debt |  |  |  |  |  |
Debt |  |  |  |  |  |
Total debt |  | 27,600 | 48,400 |  |  |
Scheduled maturities of debt: |  |  |  |  |  |
Total debt |  | 27,600 | 48,400 |  |  |
Debt agreements |  |  |  |  |  |
Debt |  | 27,600 | 48,400 |  |  |
Outstanding letters of credit |  | 301,000 | 236,400 |  |  |
Unsecured Credit Facilities |  |  |  |  |  |
Debt |  |  |  |  |  |
Total debt |  | 712,500 | 750,000 |  |  |
Scheduled maturities of debt: |  |  |  |  |  |
Total debt |  | 712,500 | 750,000 |  |  |
Debt agreements |  |  |  |  |  |
Debt |  | 712,500 | 750,000 |  |  |
Remaining borrowing capacity under the credit facility |  | 327,400 | 331,800 |  |  |
Revolving Credit Facility |  |  |  |  |  |
Debt |  |  |  |  |  |
Total debt |  |  | 114,700 |  |  |
Scheduled maturities of debt: |  |  |  |  |  |
Total debt |  |  | 114,700 |  |  |
Debt agreements |  |  |  |  |  |
Debt |  |  | 114,700 |  |  |
The 2024 Notes |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Principal amount |  | $ 800,000 |  |  |  |
Interest rate (as a percent) |  | 5.875% |  |  |  |
Line of Credit |  |  |  |  |  |
Debt |  |  |  |  |  |
Total debt |  |  | 114,700 |  |  |
Scheduled maturities of debt: |  |  |  |  |  |
Total debt |  |  | 114,700 |  |  |
Debt agreements |  |  |  |  |  |
Debt |  |  | 114,700 |  |  |
Borrowing capacity |  |  |  |  | $ 1,050,000 |
Outstanding letters of credit |  | $ 12,100 | $ 35,500 |  |  |
Remaining borrowing capacity under the credit facility |  | $ 1,037,900 |  |  |  |
Line of Credit | Maximum |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Percentage of commitment fee |  | 0.35% |  |  |  |
Line of Credit | Minimum |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Percentage of commitment fee |  | 0.125% |  |  |  |
Line of Credit | Base Rate [Member] | Maximum |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Interest rate, basis spread (as a percent) |  | 1.25% |  |  |  |
Line of Credit | Base Rate [Member] | Minimum |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Interest rate, basis spread (as a percent) |  | 0.125% |  |  |  |
Line of Credit | Debt Instrument Variable Rate Base Eurocurrency Rate | Maximum |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Interest rate, basis spread (as a percent) |  | 2.25% |  |  |  |
Line of Credit | Debt Instrument Variable Rate Base Eurocurrency Rate | Minimum |  |  |  |  |  |
Debt agreements |  |  |  |  |  |
Interest rate, basis spread (as a percent) |  | 1.125% |  |  |  |

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