Stockholders' Equity - Additional Information (Detail) - USD ($) |
12 Months Ended | 28 Months Ended | ||||
|---|---|---|---|---|---|---|
Nov. 25, 2014 |
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
Dec. 31, 2016 |
Aug. 18, 2014 |
|
| Schedule Of Capitalization Equity [Line Items] | ||||||
| Common stock, voting rights | Class B common stock is entitled to ten votes per share as compared to one vote per share for the Class A common stock | |||||
| Cash dividend paid per share | $ 0.13 | $ 0.11 | ||||
| Aggregate amount of cash dividends paid | $ 11,200,000 | $ 9,300,000 | ||||
| Amount approved under share purchase program | $ 20,000,000 | $ 10,000,000 | ||||
| Additional share amount added to repurchase program | $ 10,000,000 | |||||
| Aggregate purchase price of repurchased shares | $ 12,543,000 | |||||
| Class A common stock | ||||||
| Schedule Of Capitalization Equity [Line Items] | ||||||
| Number of shares repurchased | 0 | 2,500,000 | ||||
| Average price of repurchased shares | $ 5.08 | |||||
| Aggregate purchase price of repurchased shares | $ 12,500,000 | |||||