Debt - Term Loans (Details) $ in Thousands	9 Months Ended
Jun. 30, 2019 USD ($) loan installment	Dec. 31, 2018 loan
Debt Instrument [Line Items]
Deferred financing costs	$ 5,831
Outstanding principal balance	$ 546,905
Secured Debt \| Five-year Term Loans Maturing 2021
Debt Instrument [Line Items]
Number of term loans \| loan	3	3
Debt instrument, term (in years)	5 years
Face amount	$ 3,300
Number of installments \| installment	8
Installment payment, percentage of initial principal amount (as a percent)	12.50%
Deferred financing costs	$ 0
Outstanding principal balance	$ 1,700
Secured Debt \| Five-year Term Loans Maturing 2021 \| London Interbank Offered Rate (LIBOR)
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate (as a percent)	3.10%
Secured Debt \| One-year Term Loans Maturing 2019
Debt Instrument [Line Items]
Number of term loans \| loan	2	2
Debt instrument, term (in years)	1 year
Face amount	$ 3,200
Secured Debt \| One-year Term Loans Maturing 2019, Loan One
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage (as a percentage)	4.56%
Secured Debt \| One-year Term Loans Maturing 2019, Loan Two
Debt Instrument [Line Items]
Debt instrument, interest rate, stated percentage (as a percentage)	4.35%

Debt Instrument, Installment Payment, Percentage of Principal

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- Definition

Debt Instrument, Number of Installments

+ References

No definition available.

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- Definition

Debt Instruments, Number

+ References

No definition available.

+ Details

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- Definition

Percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
-URI http://asc.fasb.org/extlink&oid=109500613&loc=SL6031897-161870

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=119400593&loc=d3e572229-122910

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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- Definition

Face (par) amount of debt instrument at time of issuance.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28551-108399

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Section 55
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-URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400

+ Details

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.17)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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-Section 45
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-URI http://asc.fasb.org/extlink&oid=114775744&loc=d3e28555-108399

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