Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	[1]
Statement of Comprehensive Income [Abstract]
Net income	$ 4,309	$ 8,241	$ 13,296	$ 17,823	[2]
Other comprehensive income (loss):
Unrealized gain (loss) on available-for-sale securities, net of income tax expense (benefit) of $13, $13, $6 and $(4)	40	22	37	(6)
Gain (loss) on derivative securities, effective portion, net of income tax expense (benefit) of $(6), $14, $26 and $79	(18)	23	138	130
Foreign currency translation, net of income tax expense of $7, $1, $7 and $3	82	371	(373)	772
Net other comprehensive income (loss) during period	104	416	(198)	896
Comprehensive income	$ 4,413	$ 8,657	$ 13,098	$ 18,719

[1] See Note 2.

[2] See Note 2.