Goodwill (Tables)

12 Months Ended

Dec. 31, 2016

Goodwill and Intangible Assets Disclosure [Abstract]

Changes in Carrying Value of Goodwill

Goodwill consists of the following:

	As of December 31,
	2016			2015
	(in thousands)
Balance, January 1	$	209,024		$	130,976
Cogent acquisition	—			93,116
Foreign currency translation adjustments	(838		)	(15,068		)
Balance, December 31	$	208,186		$	209,024