Earnings Per Share - Basic and Diluted Weighted Average Shares Outstanding Used to Compute Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Earnings Per Share Basic And Diluted [Abstract]
Basic weighted average shares outstanding	37,386	37,066	37,343	37,053
Dilutive effect of stock options and restricted stock	774	929	786	860
Diluted weighted average shares outstanding	38,160	37,995	38,129	37,913