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 |