Consolidated Statements of Income (unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Revenues
Total revenues	$ 128,800	$ 98,227	$ 282,716	$ 217,735
Cost of revenues
Operating expenses	17,677	15,609	38,245	30,695
Depreciation and amortization	3,254	2,267	6,291	4,327
Total cost of revenues	20,931	17,876	44,536	35,022
Administrative expenses
Sales and marketing	31,647	27,430	63,999	53,009
Research and development	10,731	8,095	21,981	14,892
General and administrative	18,995	23,594	51,652	38,844
Depreciation and amortization	3,459	2,440	6,491	4,666
Total administrative expenses	64,832	61,559	144,123	111,411
Total operating expenses	85,763	79,435	188,659	146,433
Operating income	43,037	18,792	94,057	71,302
Interest expense	(34)	(281)	(34)	(538)
Other income, net	515	149	1,545	244
Income before income taxes	43,518	18,660	95,568	71,008
Provision for income taxes	7,796	(1,356)	18,686	17,298
Net income	$ 35,722	$ 20,016	$ 76,882	$ 53,710
Earnings per share, basic	$ 0.62	$ 0.34	$ 1.33	$ 0.93
Earnings per share, diluted	$ 0.61	$ 0.34	$ 1.31	$ 0.91
Weighted average shares outstanding:
Basic	57,837,312	57,898,914	57,815,290	57,623,107
Diluted	58,720,785	58,816,442	58,766,903	58,817,181
Recurring [Member]
Revenues
Total revenues	$ 126,609	$ 96,351	$ 278,494	$ 214,265
Implementation and Other [Member]
Revenues
Total revenues	$ 2,191	$ 1,876	$ 4,222	$ 3,470