Related Parties - Assets and Liabilities (Details) - USD ($) $ in Thousands		Mar. 31, 2021	Dec. 31, 2020
ASSETS
Accounts receivable, net	[1]	$ 185,103	$ 124,064
Prepaid expenses and other current assets	[1]	33,696	56,295
Prepaid expenses and other noncurrent assets, net of allowances	[1]	6,218	5,773
Liabilities
Accounts payable	[1]	78,574	31,975
Accrued liabilities	[1]	61,069	73,242
Affiliated Entity
ASSETS
Accounts receivable, net		8,615	9,474
Prepaid expenses and other current assets		50	51
Prepaid expenses and other noncurrent assets, net of allowances		4,634	4,554
Liabilities
Accounts payable		1,898	2,509
Accrued liabilities		988	1,520
Reserve for claims and performance-based arrangements		$ 202	$ 435

[1] See Note 19 for amounts attributable to unconsolidated related parties included in these line items.