Stockholders' Deficit - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Sep. 07, 2017	Dec. 31, 2017	Dec. 31, 2016
Preferred stock, shares authorized		5,000,000	5,000,000
Preferred stock, shares outstanding		0	0
Common stock, shares authorized		400,000,000	400,000,000
Public issuance of common stock		4,945,000
Net proceeds from sale of stock		$ 649,387
Public Offering
Public issuance of common stock	4,945,000
Per share price	$ 131.46
Net proceeds from sale of stock	$ 649,400
Over-Allotment Option | Maximum
Underwriter purchase option period	30 days
Shares available for purchase by underwriter (in shares)	741,750