Earnings Per Share - Basic and Diluted Weighted Average Shares Outstanding Used to Compute Earnings Per Share (Detail) - shares shares in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share Basic And Diluted [Abstract]
Basic weighted average shares outstanding	37,340	37,049	37,322	37,046
Dilutive effect of stock options and restricted stock	813	861	793	825
Diluted weighted average shares outstanding	38,153	37,910	38,115	37,871