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