Fair Value Measurements - Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended	9 Months Ended
	Apr. 30, 2019	Dec. 31, 2021	Jun. 30, 2022	Jun. 30, 2021	Sep. 30, 2021	Mar. 31, 2019
Financial assets:
Other investments			$ 18,000	$ 0	$ 0
Carrying Value
Financial assets:
Other investments			18,000
Estimated Fair Value
Financial assets:
Other investments			18,000
Estimated Fair Value | Level 1
Financial assets:
Other investments			0
Estimated Fair Value | Level 2
Financial assets:
Other investments			0
Estimated Fair Value | Level 3
Financial assets:
Other investments			$ 18,000
2.89% promissory note receivable due April 2024
Financial assets:
Notes receivable, fair value	$ 1,100					$ 1,100
Financial liabilities:
Interest on note receivable	2.89%	2.89%	2.89%	2.89%
2.89% promissory note receivable due April 2024 | Carrying Value
Financial assets:
Notes receivable, fair value			$ 1,207	$ 1,173	1,181
2.89% promissory note receivable due April 2024 | Estimated Fair Value
Financial assets:
Notes receivable, fair value			1,207	1,173	1,181
2.89% promissory note receivable due April 2024 | Estimated Fair Value | Level 1
Financial assets:
Notes receivable, fair value			0	0	0
2.89% promissory note receivable due April 2024 | Estimated Fair Value | Level 2
Financial assets:
Notes receivable, fair value			0	0	0
2.89% promissory note receivable due April 2024 | Estimated Fair Value | Level 3
Financial assets:
Notes receivable, fair value			1,207	1,173	1,181
Investments in unconsolidated affiliates | Carrying Value
Financial assets:
Investments in unconsolidated affiliates			43,384	35,387	37,724
Investments in unconsolidated affiliates | Estimated Fair Value
Financial assets:
Investments in unconsolidated affiliates			47,973	43,440	48,954
Investments in unconsolidated affiliates | Estimated Fair Value | Level 1
Financial assets:
Investments in unconsolidated affiliates			41,342	35,970	41,638
Investments in unconsolidated affiliates | Estimated Fair Value | Level 2
Financial assets:
Investments in unconsolidated affiliates			0	0	0
Investments in unconsolidated affiliates | Estimated Fair Value | Level 3
Financial assets:
Investments in unconsolidated affiliates			6,631	7,470	7,316
2024 Convertible Notes | Carrying Value
Financial liabilities:
Debt instruments, fair value			142,404	121,910	123,543
2024 Convertible Notes | Estimated Fair Value
Financial liabilities:
Debt instruments, fair value			143,951	150,219	153,281
2024 Convertible Notes | Estimated Fair Value | Level 1
Financial liabilities:
Debt instruments, fair value			0	0	0
2024 Convertible Notes | Estimated Fair Value | Level 2
Financial liabilities:
Debt instruments, fair value			143,951	150,219	153,281
2024 Convertible Notes | Estimated Fair Value | Level 3
Financial liabilities:
Debt instruments, fair value			0	0	0
2025 Convertible Notes | Carrying Value
Financial liabilities:
Debt instruments, fair value			170,117	138,722	140,643
2025 Convertible Notes | Estimated Fair Value
Financial liabilities:
Debt instruments, fair value			144,555	154,129	155,250
2025 Convertible Notes | Estimated Fair Value | Level 1
Financial liabilities:
Debt instruments, fair value			0	0	0
2025 Convertible Notes | Estimated Fair Value | Level 2
Financial liabilities:
Debt instruments, fair value			144,555	154,129	155,250
2025 Convertible Notes | Estimated Fair Value | Level 3
Financial liabilities:
Debt instruments, fair value			$ 0	$ 0	$ 0