Revenue Recognition - (Textual 2) (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation	$ 3.9
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-10-01
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation	3.3
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation	$ 0.6
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period