Stock Repurchase Program - Additional Information (Detail) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2008	Dec. 31, 2007
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program					$ 23,100,000	$ 5,000,000
Stock repurchase program expiration date			Sep. 19, 2014
Repurchase of common stock	27,000	142,000	43,000	142,000
Aggregate purchase price common stock	$ 192,000	$ 962,000	$ 306,000	$ 962,000
Prior Stock Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program expiration date			Sep. 23, 2016