Fair Value Measurements - Additional Disclosures (Details)			1 Months Ended		3 Months Ended		12 Months Ended
	Oct. 27, 2017	Oct. 26, 2017	Sep. 30, 2019 USD ($) term	Mar. 31, 2019 USD ($)	Sep. 30, 2019 USD ($) term	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) term	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($) loan	Jun. 30, 2019 USD ($)	Apr. 30, 2019 USD ($)	Jun. 30, 2014
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Additional percentage of equity interest			43.00%
Purchase price of additional equity interest			$ 1
Noncontrolling interest amount			2,800,000		$ 2,800,000		$ 2,800,000
Loss on deconsolidation							$ 300,000
Loss on expiration of call option					1,900,000
Ownership percentage after dilution							0.13
Amount received in previously escrowed seller funds				$ 1,100,000
Gain on restructured notes receivable									$ 3,000,000.0
Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restructured notes receivable, estimated settlement amount									$ 14,000,000.0
2019 Convertible Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Stated interest rate												2.125%
Not primary beneficiary, variable interest
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Principal collections on notes receivable			6,000,000.0				$ 34,100,000	$ 32,400,000
Number of promissory notes outstanding | loan									2
Notes receivable, related party									$ 60,900,000
Notes receivable outstanding balance									18,300,000
Restructured notes receivable, estimated settlement amount									14,000,000.0
Adjusted deferred compensation fee with early loan repayment										$ 10,000,000.0
Gain on restructured notes receivable						$ 3,000,000.0
Dollars denominated notes interest | Not primary beneficiary, variable interest
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, interest rate	10.00%	4.00%
Pesos denominated notes interest | Not primary beneficiary, variable interest
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Notes receivable, interest rate	14.50%	7.50%
Fee Due Date One | Not primary beneficiary, variable interest
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restructured notes receivable, estimated settlement amount			6,000,000.0		6,000,000.0		6,000,000.0		6,000,000.0
Fee Due Date Two | Not primary beneficiary, variable interest
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restructured notes receivable, estimated settlement amount									4,000,000.0
Fee Due Date Three | Not primary beneficiary, variable interest
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restructured notes receivable, estimated settlement amount									$ 4,000,000.0
Fee Due Date Two and Three | Not primary beneficiary, variable interest
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Restructured notes receivable, estimated settlement amount			$ 8,000,000.0		$ 8,000,000.0		$ 8,000,000.0
Escrow subject to indemnification claims | Not primary beneficiary, variable interest
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Escrow deposit						4,100,000		4,100,000
Measurement Input, Discount Rate | Notes receivable, net (including accreted deferred compensation of $9.2 million and $0.1 million as of September 30, 2018 and 2017, respectively) | Level 3 | Income Approach Valuation Technique | Minimum
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value assumptions, discount rate			0.07		0.07		0.07
Measurement Input, Expected Term | Notes receivable, net (including accreted deferred compensation of $9.2 million and $0.1 million as of September 30, 2018 and 2017, respectively) | Not primary beneficiary, variable interest
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Debt instrument, expected term input | term			2		2		2
Retained Investment in Subsidiary
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity interest				5.00%
Convertible Promissory Note, Zero-Coupon, Due 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Non-interest bearing convertible promissory note				$ 9,100,000
Ownership interest				10.00%
Fair value of notes receivable			$ 6,800,000		$ 6,800,000		$ 6,800,000
Secured Promissory Note 2.89%, Due 2024
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair value of notes receivable											$ 1,100,000
Notes receivable, interest rate				2.89%			2.89%
Carrying Value | 2019 Convertible Notes
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible promissory note						$ 187,433,000		$ 187,433,000
Carrying Value | Convertible Promissory Note, Zero-Coupon, Due 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Convertible promissory note			$ 7,400,000		$ 7,400,000		$ 7,400,000