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Revenue from Contracts with Customers Revenue from Contracts with Customers (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Acquisition [Line Items]
Performance obligation satisfied in previous period		$ 6,300,000	$ 0	$ 6,300,000	$ 18,100,000
Change in estimate of transaction price		0	0	0	0
Loss on contracts		4,700,000	$ 0	5,500,000	$ 0
Change in net contract liabilities				83,300,000
Contract asset impairment				0
Remaining performance obligations		$ 3,969,668,000		3,969,668,000
Cumulative effect on retained earnings, net of tax	[1]			854,000
2018 Acquisitions
Business Acquisition [Line Items]
Increase (decrease) in contract assets from acquisitions				300,000
Increase (decrease) in contract liabilities from acquisitions				$ 2,100,000
[1] Represents adjustment to retained earnings upon the adoption of Accounting Standards Codification Topic 606.

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Amount of increase (decrease) in net contract assets and liabilities.

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Amount of credit loss recognized for write-down of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

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Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in estimate of transaction price which increases (decreases) right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time. Includes, but is not limited to, change in assessment of whether estimate of variable consideration is constrained.

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Amount of revenue recognized from performance obligation satisfied or partially satisfied in previous reporting periods. Includes, but is not limited to, change in transaction price.

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Amount of the cumulative effect on retained earnings net of related income tax effect.

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Losses recognized in the current period on contracts which are expected to generate losses, which are probable and can be reasonably estimated, in a future period.

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