Segment Reporting and Significant Concentration (Tables)

12 Months Ended

Dec. 31, 2017

Segment Reporting [Abstract]

Summary of Financial Information Relating to Operations by Geographic Region

Financial information relating to our operations by geographic region is as follows (in thousands):

Total Revenues:

	2017		2016		2015
Americas (principally the U.S.)	$	669,712	$	652,376	$	634,389
Europe, Middle East and Africa (principally Europe)		72,120		69,425		78,711
Asia Pacific		47,750		39,157		39,420
Total revenues	$	789,582	$	760,958	$	752,520

Property and Equipment:	As of December 31,
	2017		2016
Americas (principally the U.S.)	$	40,286	$	28,003
Europe, Middle East and Africa (principally Europe)		2,392		2,749
Asia Pacific		1,973		2,364
Total property and equipment	$	44,651	$	33,116

Summary of Revenues from Significant Clients

Revenues from these clients represented the following percentages of our total revenues for the following years:

	2017			2016			2015
Comcast		28	%		26	%		24	%
Charter		22	%		21	%		21	%
DISH		11	%		13	%		14	%

Summary of Net Billed Accounts Receivable from Significant Clients

As of December 31, 2017 and 2016, the percentage of net billed accounts receivable balances attributable to these clients were as follows:

	As of December 31,
	2017			2016
Comcast		26	%		25	%
Charter		32	%		24	%
DISH		8	%		10	%