Derivatives and Hedging Activity - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) related to hedge ineffectiveness		$ (0.2)	$ 1.6	$ 0.7
Scenario, Forecast [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Estimated pretax gains to be reclassified from accumulated other comprehensive loss into earnings	$ 2.7