Basis of Presentation, Summary of Significant Accounting Policies and Change in Accounting Principle - Goodwill (Details) - 12 months ended Dec. 31, 2018	reporting_unit	unit
Accounting Policies [Abstract]
Number of reporting units for goodwill testing	3	3

Number of reporting units tested for impairment of goodwill. A reporting unit is an operating segment or one level below an operating segment.

No definition available.

Name:	us-gaap_NumberOfReportingUnits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration