Schedule of Financial Instruments Where Carrying Value and Fair Value Differ (Detail) $ in Millions	Dec. 31, 2016 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term obligations, excluding capital leases	$ 95.7
Fair Value Inputs Level 2 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Long-term obligations, excluding capital leases	$ 97.8