Accounts Receivable Securitization (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2016
Accounts Notes And Loans Receivable [Line Items]
Trade accounts receivable balance sold	$ 211,300,000	$ 145,300,000
Proceeds from collection of receivables	179,700,000	$ 172,500,000
Sales of trade receivables	38,800,000		$ 38,800,000	$ 19,500,000
Average collection cycle for accounts receivable (in days) (less than)			60 days
Fair value of deferred purchase price notes	66,500,000		$ 66,500,000	$ 30,600,000
Maximum
Accounts Notes And Loans Receivable [Line Items]
Capacity of securitization program	$ 75,000,000		$ 75,000,000