Unaudited Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues
Total revenues	$ 256,194	$ 196,532	$ 770,538	$ 620,487
Cost of revenues
Operating expenses	34,766	24,278	92,612	71,651
Depreciation and amortization	7,914	6,634	22,751	18,865
Total cost of revenues	42,680	30,912	115,363	90,516
Administrative expenses
Sales and marketing	69,745	62,146	200,485	173,228
Research and development	31,077	21,772	84,012	65,171
General and administrative	59,980	40,516	160,234	121,487
Depreciation and amortization	9,407	7,150	25,503	20,209
Total administrative expenses	170,209	131,584	470,234	380,095
Total operating expenses	212,889	162,496	585,597	470,611
Operating income	43,305	34,036	184,941	149,876
Interest expense				(19)
Other income (expense), net	244	246	1,019	(522)
Income before income taxes	43,549	34,282	185,960	149,335
Provision for income taxes	13,170	6,800	38,687	30,249
Net income	$ 30,379	$ 27,482	$ 147,273	$ 119,086
Earnings per share, basic	$ 0.52	$ 0.48	$ 2.55	$ 2.07
Earnings per share, diluted	$ 0.52	$ 0.47	$ 2.53	$ 2.04
Weighted average shares outstanding:
Basic	57,935	57,603	57,843	57,609
Diluted	58,190	58,171	58,192	58,312
Recurring [Member]
Revenues
Total revenues	$ 251,306	$ 192,664	$ 756,665	$ 609,109
Implementation and Other [Member]
Revenues
Total revenues	$ 4,888	$ 3,868	$ 13,873	$ 11,378