Stockholders' Equity - Summary of Share Repurchases (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended			47 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Equity, Class of Treasury Stock [Line Items]
Shares repurchased in association with tax withholdings on the vesting of RSUs	40,356	30,119	32,457
Class A common stock
Equity, Class of Treasury Stock [Line Items]
Shares repurchased pursuant to repurchase authorizations	0	2,112,370	329,000	3,155,095
Total purchase price (in millions)	$ 0.0	$ 179.0	$ 30.5
Average purchase price per share (in dollars per share)	$ 0	$ 84.72	$ 92.79	$ 84.43