Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Commitments and Contingencies [Line Items]
Provision for transition tax	$ 37.2	$ 37.2
Other Long-term Liabilities
Commitments and Contingencies [Line Items]
Transition tax	$ 28.9	$ 28.9