Stockholders' Equity - Additional Information (Detail) - USD ($) |
6 Months Ended | |||
|---|---|---|---|---|
Jun. 30, 2017 |
Jun. 30, 2016 |
Apr. 17, 2015 |
Nov. 06, 2013 |
|
| Equity, Class of Treasury Stock [Line Items] | ||||
| Share repurchase program authorized amount | $ 175,000,000 | $ 125,000,000 | ||
| Share repurchase program additional authorized amount | $ 50,000,000 | |||
| Treasury stock value | $ 7,984,000 | $ 7,096,000 | ||
| Share Repurchase Program | ||||
| Equity, Class of Treasury Stock [Line Items] | ||||
| Treasury stock shares acquired | 200,000 | 300,000 | ||
| Treasury stock value | $ 7,300,000 | $ 6,800,000 | ||
| Treasury stock shares acquired cost per share excluding commissions | $ 29.58 | |||
| Treasury stock available for repurchase | $ 70,800,000 | $ 82,200,000 | ||
| Minimum tax withholding obligations | ||||
| Equity, Class of Treasury Stock [Line Items] | ||||
| Treasury stock shares acquired | 21,000 | 11,000 | ||
| Treasury stock value | $ 600,000 | $ 300,000 | ||