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Credit Facilities - Senior Secured Notes due 2025 (Details) - USD ($) |  |  | 12 Months Ended
--- | --- | --- | ---
Sep. 01, 2020 | Jun. 11, 2020 | Sep. 30, 2020
Debt Instrument [Line Items] |  |  |
Debt instrument, face amount |  | $ 350,000,000 |
Debt instrument offering price, percentage |  | 98.50% | 8.625%
Debt issuance costs, gross |  |  | $ 9,500,000
Debt instrument, redemption price, percentage | 100.00% | 108.625% | 100.00%
Debt instrument, redemption price, percentage of principal amount redeemed |  |  | 40.00%
Debt instrument remaining outstanding |  |  | $ 500,000
Senior Notes [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Debt instrument, face amount | $ 91,500,000 |  | $ 100,000,000.0
Debt instrument, redemption price, percentage |  | 100.00% | 103.00%
Debt instrument, redemption price, percentage of principal amount redeemed |  |  | 103.00%
Debt instrument, conversion price (in dollars per share) |  |  | $ 6.00
Senior Notes [Member] | Gain Capital Holdings Inc [Member] |  |  |
Debt Instrument [Line Items] |  |  |
Debt instrument, face amount |  |  | $ 92,000,000.0
Debt instrument, interest rate, stated percentage |  |  | 5.00%

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- Definition The price per share of the conversion feature embedded in the debt instrument. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 470 -SubTopic 20 -Section 50 -Paragraph 5 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=120520924&loc=SL6031898-161870 + 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=119993939&loc=d3e28551-108399 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=114775985&loc=d3e28878-108400 + Details
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- Definition Percentage price of original principal amount of debt at which debt can be redeemed by the issuer. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 470 -Section 50 -Paragraph 3 -Subparagraph e -URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823 + Details
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- Definition Amount, before 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 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=119993939&loc=d3e28555-108399 + Details
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