Accounts Receivable (Tables)

12 Months Ended

Dec. 31, 2016

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

Schedule of 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

Schedule of Activity in the Accounts Receivable Reserves

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