Stock-Based Compensation - Stock Options (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Options (in shares):
Outstanding beginning of the period (in shares)	4,353,167
Granted (in shares)	0	0
Forfeited (in shares)	(21,735)
Exercised (in shares)	(225,310)
Outstanding end of the period (in shares)	4,106,122		4,353,167
Exercisable (in shares)	3,703,584
Weighted-Average Exercise Price (in dollars per share):
Outstanding beginning of the period (in dollars per share)	$ 14.32
Granted (in dollars per share)	0
Forfeited (in dollars per share)	20.50
Exercised (in dollars per share)	12.40
Outstanding end of the period (in dollars per share)	14.39		$ 14.32
Exercisable (in dollars per share)	$ 14.01
Outstanding, weighted-average remaining contractual term (years)	5 years 4 months 24 days		5 years 7 months 6 days
Exercisable, weighted-average remaining contractual term (years)	5 years 2 months 12 days
Outstanding, aggregate intrinsic value	$ 73,653		$ 120,714
Exercisable, aggregate intrinsic value	67,834
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options exercised intrinsic value	6,600	$ 34,300
Options vested in period fair value	1,400	$ 2,700
Options unrecognized compensation expense	$ 2,500
Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options unrecognized compensation expense, period for recognition (years)	1 year 2 months 12 days
Class A Common Stock | Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Expiration period (years)	10 years
Minimum | Class A Common Stock | Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Award vesting period (years)	3 years
Maximum | Class A Common Stock | Employee stock options
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Award vesting period (years)	4 years