Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Statement of Comprehensive Income [Abstract]
Net income	$ 69,336	$ 57,304	$ 40,440
Other Comprehensive Income (Loss), Securities, Available-for-sale, Adjustment, before Reclassification Adjustments, after Tax	1,367	(261)
Change in net unrealized loss on investments, net of tax			(462)
Reclassification adjustment for net loss realized and included in net income, net of tax effects of $0 in fiscal years 2019, 2018 and 2017.	0	289	44
Total change in unrealized gain (loss) on marketable securities, net of taxes	1,367	28	(418)
Other comprehensive income (loss), net of tax	1,748	(12)	(418)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification and Tax	515	(40)	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	134	0	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification and Tax	381	(40)	0
Comprehensive income	$ 71,084	$ 57,292	$ 40,022