Allowance for Doubtful Account (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at December 31, 2016	$ 7.4
2017 Charges	0.8	$ 1.6
2017 Charge- offs, Net of Recoveries	0.6
Balance at June 30, 2017	7.6
Total trade receivables
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at December 31, 2016	7.4
2017 Charges	0.8
2017 Charge- offs, Net of Recoveries	0.6
Balance at June 30, 2017	7.6
Trade accounts receivable
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at December 31, 2016	7.1
2017 Charges	0.8
2017 Charge- offs, Net of Recoveries	(0.6)
Balance at June 30, 2017	7.3
Trade notes receivable
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at December 31, 2016	0.3
2017 Charges	0.0
2017 Charge- offs, Net of Recoveries	0.0
Balance at June 30, 2017	0.3
Other notes receivable
Allowance for Doubtful Accounts Receivable [Roll Forward]
Balance at December 31, 2016	0.0
2017 Charges	0.0
2017 Charge- offs, Net of Recoveries	0.0
Balance at June 30, 2017	$ 0.0