Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Total revenues	$ 1,189,346	$ 1,048,782	$ 1,002,286
Operating Expenses:
Cost of revenues (excluding depreciation and amortization)	511,084	426,995	404,954
Sales and marketing	363,111	311,433	313,251
Engineering and development	69,460	52,139	29,630
General and administrative	152,672	135,324	122,537
Depreciation and amortization	86,256	70,980	72,523
Total operating expenses	1,182,583	996,871	942,895
Income from operations	6,763	51,911	59,391
Other Income (Expense):
Interest expense	(32,821)	(15,068)	(14,868)
Other income (expense), net	(50)	(318)	1,270
Total other income (expense), net	(32,871)	(15,386)	(13,598)
(Loss) Income before income taxes	(26,108)	36,525	45,793
Income tax benefit (expense)	6,626	(797)	(79,726)
Net (loss) income	$ (19,482)	$ 35,728	$ (33,933)
(Loss) Earnings per common share:
Basic (loss) earnings per share	$ (0.08)	$ 0.15	$ (0.15)
Diluted (loss) earnings (loss) per share	$ (0.08)	$ 0.14	$ (0.15)
Weighted-average common shares outstanding:
Basic weighted average common shares outstanding	242,018	237,499	225,311
Diluted	242,018	248,892	225,311