Revenue Recognition - Narrative (Details)	3 Months Ended
	Mar. 31, 2019
Revenue from Contract with Customer [Abstract]
Payment terms	20 days
Minimum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Unsatisfied performance obligations	1 year
Maximum
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Unsatisfied performance obligations	15 years