Contingencies (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Commitments and Contingencies Disclosure [Abstract]
Expenses relating to investigation	$ 0.3	$ 1.0

Amount of litigation expense, including but not limited to legal, forensic, accounting, and investigative fees.

No definition available.

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