Shareholders' Equity - Additional Information (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2019 USD ($)
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, term (in years)	3 years
Stock repurchase program, remaining authorized repurchase amount	$ 94.0
October 2016 Share Repurchase Program
Equity, Class of Treasury Stock [Line Items]
Share repurchase program, authorized amount	$ 100.0