Investments - Additional Disclosures Related to Associated Company Financial Statements (Details) - USD ($) $ in Thousands	3 Months Ended						6 Months Ended		9 Months Ended
	Jun. 30, 2020	Apr. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Apr. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019	Apr. 30, 2020	Apr. 30, 2019	Dec. 31, 2019	Jul. 31, 2019
Summary of balance sheet amounts:
Current assets	$ 771,681						$ 771,681				$ 1,090,201
Total Assets	3,947,047						3,947,047				2,332,354
Current liabilities	646,846						646,846				935,821
Total Liabilities	3,517,758						3,517,758				1,855,935
Equity	425,074						425,074				472,613
Total Liabilities and Capital	3,947,047						3,947,047				$ 2,332,354
Summary operating results:
Total revenue	295,437			$ 385,715			643,337	$ 741,528
Net loss	$ (1,677)		$ (61,607)	$ 21,034		$ 15,622	$ (63,284)	$ 36,656
Multiple equity method investments
Summary of balance sheet amounts:
Current assets		$ 234,250							$ 234,250			$ 213,324
Non-current assets		550,416							550,416			518,239
Total Assets		784,666							784,666			731,563
Current liabilities		274,430							274,430			256,850
Non-current liabilities		430,910							430,910			386,835
Total Liabilities		705,340							705,340			643,685
Contingently redeemable preferred stock		35,175							35,175			35,186
Equity		44,151							44,151			52,692
Total Liabilities and Capital		784,666							784,666			$ 731,563
Summary operating results:
Total revenue		177,351			$ 194,003				392,803	$ 400,226
Gross profit		33,470			34,861				78,719	74,404
Net loss		$ (6,159)			$ (9,627)				$ (9,716)	$ (21,380)