Earnings Per Share (Detail)	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended	3 Months Ended	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Sep. 30, 2014 Options	Sep. 30, 2014 Options	Sep. 30, 2014 Restricted stock	Sep. 30, 2014 Restricted stock	Sep. 30, 2014 Employee Stock Purchase Plan	Sep. 30, 2014 Employee Stock Purchase Plan
Earnings Per Share Disclosure [Line Items]
Weighted average number of antidilutive shares excluded from the calculation of earnings per share (shares)	152,203	50,824	250,000	214,835	64,051	451,326	659	715