Stockholders' Equity - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions	6 Months Ended
Jun. 30, 2018	Dec. 31, 2017
Subsidiary, Sale of Stock [Line Items]
Class A common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Aggregate sales price	$ 200.0
Shares sold (in shares)	0
Aggregate offering price	$ 144.2

Face amount or stated value per share of common stock.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant