Revenue from Contracts with Customers - Additional Information (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenue from Contract with Customer [Abstract]
Percentage of primary source of revenue	89.50%	89.00%	89.70%	88.90%