Investments - Additional Disclosures Related to Associated Company Financial Statements (Details) - USD ($) $ in Thousands	3 Months Ended								9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Apr. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Apr. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Apr. 30, 2020	Sep. 30, 2019	Apr. 30, 2019	Dec. 31, 2019	Jul. 31, 2019
Summary of balance sheet amounts:
Current assets	$ 809,816								$ 809,816				$ 1,090,201
Total Assets	3,997,486								3,997,486				2,332,354
Current liabilities	565,566								565,566				935,821
Total Liabilities	3,527,896								3,527,896				1,855,935
Equity	465,061								465,061				472,613
Total Liabilities and Capital	3,997,486								3,997,486				$ 2,332,354
Summary operating results:
Total revenue	330,007				$ 371,080				973,344		$ 1,112,608
Net loss	$ 38,523	$ (1,677)		$ (61,607)	$ (2,764)	$ 21,034		$ 15,622	$ (24,761)		$ 33,892
Multiple equity method investments
Summary of balance sheet amounts:
Current assets			$ 223,543							$ 223,543				$ 213,324
Non-current assets			535,629							535,629				518,239
Total Assets			759,172							759,172				731,563
Current liabilities			249,932							249,932				256,850
Non-current liabilities			425,242							425,242				386,835
Total Liabilities			675,174							675,174				643,685
Contingently redeemable preferred stock			35,180							35,180				35,186
Equity			48,818							48,818				52,692
Total Liabilities and Capital			759,172							759,172				$ 731,563
Summary operating results:
Total revenue			164,857				$ 204,471			557,660		$ 604,697
Gross profit			39,994				37,126			118,713		111,530
Net loss			$ (360)				$ (37,982)			$ (10,076)		$ (59,362)