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Balance Sheet Information - Additional Information (Detail) - USD ($) | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Sep. 30, 2021 | Jul. 31, 2021 | Sep. 30, 2023 | Sep. 30, 2022 | Sep. 30, 2021 | Feb. 28, 2022
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |
Asset impairment |  |  | $ 54,343,000 | $ 171,824,000 |  |
Depreciation expense |  |  | 60,200,000 | 80,500,000 | $ 81,200,000 |
Estimated initial equity warrant asset value |  |  | 16,400,000 |  |  |
Warrant asset value |  |  | 16,400,000 |  |  |
Investments in equity securities |  |  | 20,320,000 | 15,178,000 |  |
Estimated initial warrant asset value |  |  |  |  |  | $ 3,200,000
Net gains/(losses) on investments in equity securities |  |  | 5,400,000 | (13,700,000) |  |
Aggregate carrying amount of investments in equity securities |  |  | 20,300,000 |  |  |
Investments without readily determinable fair value |  |  | 8,800,000 |  |  |
Level 3 [Member] |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |
Investments in equity securities |  |  | 3,500,000 |  |  |
Archer Aviation, Inc. [Member] |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |
Gains/(losses) on investments |  |  | 5,600,000 | (13,700,000) |  |
Archer Aviation, Inc. [Member] | Level 1 [Member] |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |
Investments in equity securities |  |  | 11,500,000 |  |  |
Heart Aerospace Incorporated [Member] | Level 3 [Member] |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |
Investments in equity securities |  |  | 5,000,000 |  |  |
Heart Aerospace Incorporated [Member] | Forward Purchase Contract [Member] | Preferred Stock [Member] |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |
Purchase of preferred stock |  | $ 5,000,000 |  |  |  |
Initial investment in preferred stock measured at cost |  | $ 5,000,000 |  |  |  |
Class A [Member] | Archer Aviation, Inc. [Member] |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |
Stock issued during period, Shares | 500,000 |  |  |  |  |
Stock issued during period, Value | $ 5,000,000 |  |  |  |  |
Total grant date value, Additional warrant to purchase shares | $ 5,600,000 |  |  |  |  |
Long Lived Assets [Member] |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |
Asset impairment |  |  | 0 |  |  |
CRJ-900 [Member] |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |
Asset impairment |  |  | 0 |  |  |
CRJ-900 [Member] | Long Lived Assets [Member] |  |  |  |  |  |
Condensed Balance Sheet Statements Captions [Line Items] |  |  |  |  |  |
Asset impairment |  |  | $ 0 | $ 116,600,000 | $ 0 |

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