Commitments and Contingencies Commitment and Contingencies (Details) $ in Millions	3 Months Ended
Mar. 31, 2018 USD ($)
Commitments and Contingencies Disclosure [Abstract]
Litigation Settlement, Amount Awarded from Other Party	$ 12.8

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

No definition available.

Name:	us-gaap_LitigationSettlementAmountAwardedFromOtherParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration