Commitments and Contingencies - Additional Information (Details) $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Pre-tax charge for litigation settlement	$ 13

Amount awarded to other party in judgment or settlement of litigation.

No definition available.

Name:	us-gaap_LitigationSettlementAmountAwardedToOtherParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration