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Borrowing Arrangements Narrative (Details) - USD ($) $ in Thousands | 6 Months Ended |  |  |
--- | --- | --- | --- | ---
Mar. 31, 2017 | Sep. 30, 2016 | Dec. 31, 2015 | Sep. 30, 2015
Cash and cash equivalents | $ 328,300 | $ 195,000 | $ 93,600 | $ 113,100
Future maturities of outstanding borrowings |  |  |  |
Debt Instrument, Unamortized Discount | 1,700 |  |  |
Domestic Line of Credit [Member] |  |  |  |
Revolving credit facility amount | (225,000) |  |  |
Potential increase size of the credit facility by an additional amount | $ 150,000 |  |  |
Line of Credit Facility, Interest Rate at Period End | 12500.00% |  |  |
Agreement termination date | Jul. 13, 2021 |  |  |
Aggregate commitments availability | $ 17,500 |  |  |
Aggregate commitments availability, percentage | 10.00% |  |  |
Outstanding letter of credit accrued fees and expenses | $ 22,200 |  |  |
Excess availability reduced by outstanding borrowings, outstanding letters of credit and accrued fees and expenses | 125,300 |  |  |
Swing Line Loans [Member] |  |  |  |
Revolving credit facility amount | (25,000) |  |  |
Letters Of Credit Outstanding [Member] |  |  |  |
Revolving credit facility amount | (60,000) |  |  |
Secured Debt [Member] |  |  |  |
Long-term Debt, Gross | $ 500,000 | $ 150,000 |  |
debt instrument, change in spread on variable rate | 7500.00% |  |  |
Debt Instrument, Basis Spread on Variable Rate | 25000.00% |  |  |
Debt Instrument, Interest Rate, Effective Percentage | 4.58% | 4.841% |  |
Debt Instrument, Periodic Payment, Principal | $ 1,225 |  |  |
Agreement termination date | Nov. 25, 2021 |  |  |
Future maturities of outstanding borrowings |  |  |  |
Financial Liabilities Fair Value Disclosure | $ 491,800 |  |  |
Minimum [Member] | Domestic Line of Credit [Member] |  |  |  |
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | 2500.00% |  |  |
London Interbank Offered Rate (LIBOR) [Member] | Secured Debt [Member] |  |  |  |
Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum | 0.75% |  |  |
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member] | Long-term Debt [Member] |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | 2500.00% |  |  |
London Interbank Offered Rate (LIBOR) [Member] | Minimum [Member] | Domestic Line of Credit [Member] |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | 12500.00% |  |  |
London Interbank Offered Rate (LIBOR) [Member] | Maximum [Member] | Domestic Line of Credit [Member] |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | 15000.00% |  |  |
Base Rate [Member] | Maximum [Member] | Domestic Line of Credit [Member] |  |  |  |
Debt Instrument, Basis Spread on Variable Rate | 5000.00% |  |  |

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- Definition Amount of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Excludes cash and cash equivalents within disposal group and discontinued operation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash -URI http://asc.fasb.org/extlink&oid=6506951 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section 45 -Paragraph 1 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=28358313&loc=d3e6676-107765 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3044-108585 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash Equivalents -URI http://asc.fasb.org/extlink&oid=6507016 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.1) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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