Related Parties - Assets and Liabilities (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
ASSETS
Accounts receivable	[1]	$ 75,667	$ 80,208
Prepaid expenses - current	[1]	28,488	22,618
Customer advance for regulatory capital requirements	[1]	40,000
Prepaid expenses and other noncurrent assets	[1]	6,253	15,028
Liabilities
Accounts payable	[1]	37,488	146,760
Accrued liabilities	[1]	33,343	48,957
Affiliated Entity
ASSETS
Accounts receivable		8,781	8,519
Prepaid expenses - current		1,592	85
Customer advance for regulatory capital requirements		40,000	0	[1]
Prepaid expenses and other noncurrent assets		2,709	2,500
Liabilities
Accounts payable		6,429	1,564
Accrued liabilities		2,583	798
Reserve for claims and performance-based arrangements		$ 4,264	$ 0

[1] See Note 18 for amounts related to related parties included in these line items.