CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Income Statement [Abstract]
Revenues	$ 391,847	$ 328,425
Cost of revenues	78,909	71,153
Gross profit	312,938	257,272
Operating expenses:
Selling and marketing (excluding customer base amortization)	125,107	88,094
Software development	41,610	27,928
General and administrative	58,873	40,076
Customer base amortization	11,484	7,682
Total operating expenses	237,074	163,780
Income from operations	75,864	93,492
Interest and other income	4,518	4,945
Interest and other expense	(2,026)	(732)
Income before income taxes	78,356	97,705
Income tax expense	5,563	12,536
Net income	$ 72,793	$ 85,169
Net income per share-basic (in dollars per share)	$ 2.00	$ 2.35
Net income per share-diluted (in dollars per share)	$ 1.98	$ 2.33
Weighted average outstanding shares-basic (in shares)	36,471	36,237
Weighted average outstanding shares-diluted (in shares)	36,776	36,567