CONSOLIDATED STATEMENTS OF OPERATIONS AND COMPREHENSIVE INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Revenue	$ 764,865	$ 617,736	$ 384,402
Costs and expenses:
Cost of revenue (exclusive of depreciation and amortization shown separately below)	36,399	17,223	13,764
Selling and marketing expense	500,291	432,784	261,100
General and administrative expense	101,219	71,541	37,227
Product development	26,958	17,925	13,761
Depreciation	7,385	7,085	4,944
Amortization of intangibles	23,468	12,992	1,243
Change in fair value of contingent consideration	10,788	23,931	0
Severance	2,352	404	122
Litigation settlements and contingencies	(186)	718	129
Total costs and expenses	708,674	584,603	332,290
Operating income	56,191	33,133	52,112
Other (expense) income, net:
Interest expense, net	(12,437)	(7,028)	(561)
Other (expense) income	(10)	(396)	23
Income before income taxes	43,744	25,709	51,574
Income tax benefit (expense)	65,575	(6,291)	(20,366)
Net income from continuing operations	109,319	19,418	31,208
Loss from discontinued operations, net of tax	(12,820)	(3,840)	(3,714)
Net income	96,499	15,578	27,494
Comprehensive income	$ 96,499	$ 15,578	$ 27,494
Weighted average shares outstanding:
Weighted average basic common shares (in shares)	12,504	11,945	11,812
Weighted average diluted common shares (in shares)	14,097	13,682	12,773
Income per share from continuing operations:
Basic (in dollars per share)	$ 8.74	$ 1.63	$ 2.64
Diluted (in dollars per share)	7.75	1.42	2.44
Loss per share from discontinued operations:
Basic (in dollars per share)	(1.03)	(0.32)	(0.31)
Diluted (in dollars per share)	(0.91)	(0.28)	(0.29)
Net income per share:
Basic (in dollars per share)	7.72	1.30	2.33
Diluted (in dollars per share)	$ 6.85	$ 1.14	$ 2.15