Commitments and Contingencies (Details) ft² in Thousands, $ in Millions	Mar. 31, 2019 USD ($) ft²	Dec. 31, 2018 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Area of office space (in sqft) \| ft²	490
Noncancelable minimum lease payments not yet commenced	$ 420.0
Secured letters of credit outstanding	$ 24.6	$ 10.6

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

No definition available.

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant