Accounts Receivable

12 Months Ended

Dec. 31, 2016

Accounts, Notes, Loans and Financing Receivable, Gross, Allowance, and Net [Abstract]

Accounts Receivable

Accounts Receivable

Net accounts receivable consisted of the following as of December 31, 2016 and 2015 (in thousands):

	December 31, 2016			December 31, 2015
Trade accounts receivable	$	260,976		$	262,885
Unbilled accounts receivable	113,765			124,878
Gross accounts receivable	374,741			387,763
Allowance for doubtful accounts	(829		)	(906		)
Reserve for cash-basis customers	(5,316		)	(6,458		)
Total accounts receivable reserves	(6,145		)	(7,364		)
Accounts receivable, net	$	368,596		$	380,399

A summary of activity in the accounts receivable reserves for the years ended December 31, 2016, 2015 and 2014, is as follows (in thousands):

	2016			2015			2014
Beginning balance	$	7,364		$	9,023		$	3,703
Charges to income from operations	49,677			37,870			32,293
Collections from cash basis customers and write-offs	(50,896		)	(39,529		)	(26,973		)
Ending balance	$	6,145		$	7,364		$	9,023

Charges to income from operations represent charges to bad debt expense for increases in the allowance for doubtful accounts and reductions to revenue for increases in reserves for cash basis customers.