Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Revenue		$ 642,410	$ 527,676	$ 449,358
Expenses:
Cost of revenue	[1]	167,814	144,826	151,046
Sales and marketing	[1]	62,411	45,534	34,103
Research and development	[1]	33,686	28,638	27,383
General and administrative	[1]	200,762	205,038	149,948
Depreciation and amortization		108,250	96,725	53,089
Restructuring expense		0	9,500	0
Total operating expenses		572,923	530,261	415,569
Income (Loss) from operations		69,487	(2,585)	33,789
Other income and (expenses):
Interest income		2,242	2,181	5,429
Interest expense		(65,831)	(50,898)	(6,225)
Other expense, net		(20)	(2,255)	(406)
Income (Loss) before taxes		5,878	(53,557)	32,587
Benefit from income taxes		(1,897)	(14,393)	(2,231)
Net income (loss)		7,775	(39,164)	34,818
Net income (loss) attributable to common stockholders, basic and diluted		$ 7,538	$ (39,164)	$ 33,828
Net income (loss) per share attributable to common stockholders, basic and diluted:
Basic net income (loss) per share (in dollars per share)		$ 0.05	$ (0.27)	$ 0.24
Diluted net income (loss) per share (in dollars per share)		$ 0.05	$ (0.27)	$ 0.24
Weighted average shares of common stock outstanding:
Basic (in shares)		148,304	145,389	142,225
Diluted (in shares)		148,633	145,389	142,737

[1] (1) Includes stock-based compensation expense as follows:           Cost of revenue $ 348
  $ 237
  $ 1,652
Sales and marketing 1,675
  735
  2,011
Research and development 1,707
  1,937
  1,293
General and administrative 16,500
  13,253
  12,362
Total stock-based compensation expense $ 20,230
  $ 16,162
  $ 17,318