Condensed Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Total revenues	$ 356,976	$ 344,141	$ 1,020,353	$ 966,466
Cost of revenues	55,822	61,716	171,755	172,995
Gross profit	301,154	282,425	848,598	793,471
Operating expenses:
Sales and marketing	95,074	98,486	287,317	273,812
Research, development and engineering	14,261	13,770	43,273	38,692
General and administrative	114,381	110,810	312,283	314,132
Total operating expenses	223,716	223,066	642,873	626,636
Income from operations	77,438	59,359	205,725	166,835
Interest expense, net	22,712	17,271	65,879	50,625
Gain on sale of businesses	(17,122)	0	(17,122)	0
Loss on investments, net	156	7	20,991	45
Other (income) expense, net	(14,230)	857	(16,413)	2,657
Income before income taxes and net loss (income) in earnings of equity method investment	85,922	41,224	152,390	113,508
Income tax expense	24,330	6,998	49,011	17,851
Net loss (income) in earnings of equity method investment	709	3,481	10,799	(126)
Net income	$ 60,883	$ 30,745	$ 92,580	$ 95,783
Net income per common share:
Basic (in usd per share)	$ 1.31	$ 0.63	$ 1.96	$ 1.98
Diluted (in usd per share)	$ 1.31	$ 0.62	$ 1.93	$ 1.93
Weighted average shares outstanding:
Basic (in shares)	46,279,515	47,673,211	46,914,750	47,654,327
Diluted (in shares)	46,309,072	49,064,272	47,620,308	48,892,523
Share-based compensation expense	$ 5,800	$ 6,446	$ 18,643	$ 18,394
Cost of revenues
Weighted average shares outstanding:
Share-based compensation expense	136	127	413	390
Sales and marketing
Weighted average shares outstanding:
Share-based compensation expense	321	419	1,135	1,212
Research, development and engineering
Weighted average shares outstanding:
Share-based compensation expense	425	373	1,340	1,092
General and administrative
Weighted average shares outstanding:
Share-based compensation expense	$ 4,918	$ 5,527	$ 15,755	$ 15,700