Fair Value Measurements - Additional Information (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Apr. 04, 2017 USD ($)
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Contingent liability, current		$ 2.3
Contingent liability, noncurrent	$ 7.8	13.6
Measurement Input, Discount period
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost of debt, discount period	3 years
Minimum | Measurement Input, Discount rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost of debt, discount rate	0.0378
Maximum | Measurement Input, Discount rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Cost of debt, discount rate	0.0493
Headway
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Fair value of contingent consideration	$ 7.8	$ 15.9	$ 15.9