Revenue from Contracts with Customers (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Business Acquisition [Line Items]
Performance obligation satisfied in previous period	$ 0	$ 6,300,000.0	$ 0	$ 6,300,000
Change in estimate of transaction price	0	0	0	0
Change in total estimated cost	0	$ 4,700,000	0	$ 5,500,000
Loss on contracts	0		0
Change in net contract liabilities			7,100,000
Contract asset impairment			0		$ 0
Remaining performance obligations	$ 4,035,088,000		4,035,088,000
2019 Acquisitions
Business Acquisition [Line Items]
Increase in contract assets from acquisitions			6,200,000
Increase in contract liabilities from acquisitions			$ 13,000,000.0