Accounts Receivable Securitization Programs (Details)	3 Months Ended
	Mar. 31, 2018 USD ($) bank	Mar. 31, 2018 EUR (€)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
U.S. Accounts Receivable Securitization Program | U.S. Program
Qualitative And Quantitative Information Transferors Continuing Involvement [Line Items]
Number of banks involved in sale of fractional ownership interest of accounts receivable | bank	2
Level of eligible assets available under accounts receivable securitization program	$ 60,000,000
Amount available for accounts receivable securitization program			$ 60,000,000
Amount utilized under accounts receivable securitization program			0	$ 0
U.S. Accounts Receivable Securitization Program | Maximum | U.S. Program
Qualitative And Quantitative Information Transferors Continuing Involvement [Line Items]
Maximum purchase limit for receivable interests under accounts receivable securitization program			60,000,000
European Accounts Receivable Securitization Program | European Program
Qualitative And Quantitative Information Transferors Continuing Involvement [Line Items]
Amount available for accounts receivable securitization program		€ 75,400,000	92,700,000
Amount utilized under accounts receivable securitization program		74,400,000	91,400,000	$ 0
European Accounts Receivable Securitization Program | Maximum | European Program
Qualitative And Quantitative Information Transferors Continuing Involvement [Line Items]
Maximum purchase limit for receivable interests under accounts receivable securitization program		€ 80,000,000	$ 98,400,000