Details of Selected Balance Sheet Accounts - Accounts Receivable (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	$ 179,040	$ 242,232
Allowance for doubtful accounts	(10,262)	(8,745)
Accounts receivable, net	$ 168,778	$ 233,487
Allowance for doubtful accounts as a percentage of total accounts receivable	6.00%	4.00%
Trade
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	$ 128,549	$ 178,813
Unbilled revenue
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	20,970	28,341
Contract assets
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	25,636	26,034
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Accounts receivable, gross	$ 3,885	$ 9,044