Revenue (Tables)

6 Months Ended

Jun. 30, 2019

Revenue from Contract with Customer [Abstract]

Summary of Total Receivables, Net

Total receivables, net is comprised of the following (in thousands):

	June 30, 2019			December 31, 2018
Billed receivables	$	158,052		$	239,275
Allowance for doubtful accounts	(3,781		)	(3,912		)
Billed receivables, net	154,271			235,363
Accrued receivables	341,417			336,858
Significant financing component	(31,782		)	(35,029		)
Total accrued receivables, net	309,635			301,829
Less: current accrued receivables	142,248			123,053
Less: current significant financing component	(10,126		)	(10,234		)
Total long-term accrued receivables, net	177,513			189,010
Total receivables, net	$	463,906		$	537,192

Summary of Changes in Deferred Revenue

Changes in deferred revenue were as follows (in thousands):

Balance, December 31, 2018	$	156,135
Deferral of revenue	79,147
Recognition of deferred revenue	(97,104		)
Foreign currency translation	255
Balance, June 30, 2019	$	138,433