Revenue Recognition - Remaining Performance Obligation (Details)	12 Months Ended
	Dec. 31, 2018 USD ($)
Revenue from Contract with Customer [Abstract]
Aggregate transaction price allocated to performance obligations	$ 58,800,000
Revenue recognized related to performance obligation	0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue from Contract with Customer [Abstract]
Aggregate transaction price allocated to performance obligations	$ 54,900,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Remaining performance obligation, expected duration	12 months