Consolidated Statements Of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Consolidated Statements Of Comprehensive Income [Abstract]
Net income (loss)	$ 10,943	$ 18,074	$ (12,698)	$ 26,629
Other comprehensive income (loss):
Foreign currency translation adjustments	(2,652)	2,513	(1,320)	3,121
Unrealized gain on investments, net of tax	41	12	41	16
Unrealized gain (loss) on derivative, net of tax	244	(200)	1,077	165
Other	0	0	0	(13)
Other comprehensive income (loss)	(2,367)	2,325	(202)	3,289
Comprehensive income (loss)	$ 8,576	$ 20,399	$ (12,900)	$ 29,918