Summary of Significant Accounting Policies - Weighted Average Shares and Share Equivalents Used to Calculate Basic and Diluted Earnings Per Share (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Abstract]
Weighted average number of shares outstanding used to calculate basic EPS (in Shares)	3,692	3,641	3,631
Dilutive securities:
Stock options and restricted share units (in Shares)	225	332	461
Weighted average number of shares and share equivalents outstanding used to calculate diluted EPS (in Shares)	3,917	3,973	4,092