Stockholders' Equity, Amendment of Certificate of Incorporation and Reclassification of Common Stock (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2018	Dec. 31, 2017	May 17, 2017	Dec. 06, 2016	Aug. 02, 2016	Jul. 28, 2016	Jan. 01, 2016
Class of Stock [Line Items]
Preferred Stock, Shares Issued	0	0
Common stock, shares authorized (in shares)	400,000,000	400,000,000				400,000,000	18,333,333
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01				$ 0.01	$ 0.0001
Preferred stock, shares authorized (in shares)						100,000,000
Preferred stock, outstanding (in shares)	0	0
Preferred stock, par value (in dollars per share)						$ 0.01
Share price (in dollars per share)			$ 33.00	$ 27.50
Class A Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares authorized (in shares)							15,000,000
Accrued and unpaid dividends						$ 90.3
Conversion rate to reclassify class A shares to common stock						65.48598%
Class B Common Stock [Member]
Class of Stock [Line Items]
Common stock, shares authorized (in shares)							3,333,333
Conversion rate to reclassify class B shares to common stock						72.09506%
IPO [Member]
Class of Stock [Line Items]
Share price (in dollars per share)					$ 16.00	$ 16.00