Fair Value Measurements - Financial Assets and Liabilities (Details) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended		12 Months Ended
	Apr. 30, 2019	Dec. 31, 2021	Dec. 31, 2020	Sep. 30, 2021	Mar. 31, 2019
Financial assets:
Other investments		$ 16,500	$ 0	$ 0
Carrying Value
Financial assets:
Other investments		16,500
Estimated Fair Value
Financial assets:
Other investments		16,500
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		$ 16,500
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		$ 1,190	$ 1,156	$ 1,181
2.89% promissory note receivable due April 2024 | Estimated Fair Value
Financial assets:
Notes receivable, fair value		1,190	1,156	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		1,190	1,156	1,181
Investments in unconsolidated affiliates | Carrying Value
Financial assets:
Investments in unconsolidated affiliates		42,513	31,773	37,724
Investments in unconsolidated affiliates | Estimated Fair Value
Financial assets:
Investments in unconsolidated affiliates		52,671	44,716	48,954
Investments in unconsolidated affiliates | Estimated Fair Value | Level 1
Financial assets:
Investments in unconsolidated affiliates		45,650	37,039	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		7,021	7,677	7,316
2024 Convertible Notes | Carrying Value
Financial liabilities:
Debt instruments, fair value		142,106	118,736	123,543
2024 Convertible Notes | Estimated Fair Value
Financial liabilities:
Debt instruments, fair value		147,063	134,838	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		147,063	134,838	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		169,738	134,983	140,643
2025 Convertible Notes | Estimated Fair Value
Financial liabilities:
Debt instruments, fair value		155,060	138,000	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		155,060	138,000	155,250
2025 Convertible Notes | Estimated Fair Value | Level 3
Financial liabilities:
Debt instruments, fair value		$ 0	$ 0	$ 0
8.5% unsecured debt due 2024
Financial liabilities:
Stated interest rate			8.50%
8.5% unsecured debt due 2024 | Carrying Value
Financial liabilities:
Debt instruments, fair value			$ 816
8.5% unsecured debt due 2024 | Estimated Fair Value
Financial liabilities:
Debt instruments, fair value			816
8.5% unsecured debt due 2024 | Estimated Fair Value | Level 1
Financial liabilities:
Debt instruments, fair value			0
8.5% unsecured debt due 2024 | Estimated Fair Value | Level 2
Financial liabilities:
Debt instruments, fair value			0
8.5% unsecured debt due 2024 | Estimated Fair Value | Level 3
Financial liabilities:
Debt instruments, fair value			$ 816