Stockholders' Equity - Contribution of Class A Common Shares (Details) - USD ($) shares in Millions		3 Months Ended		9 Months Ended
	Sep. 10, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Restricted Stock Units
Limited Partners' Capital Account [Line Items]
Issuance of stock (in shares)		0.1	0.2	0.2	0.2
Class A Common Stock | Restricted Stock Units
Limited Partners' Capital Account [Line Items]
Issuance of stock (in shares)		0.1	0.2	0.2	0.2
Chief Executive Officer | Contribution Agreement | Restricted Stock Units
Limited Partners' Capital Account [Line Items]
Contribution of Class A common stock from related party, fee charged	$ 0
Chief Executive Officer | Class A Common Stock | Contribution Agreement
Limited Partners' Capital Account [Line Items]
Contribution of Class A common stock from related party (in shares)		0.1	0.2	0.2	0.2
Contribution of Class A common stock from related party, fee charged		$ 0	$ 0	$ 0	$ 0