Stock-Based Compensation - Summary of Activity for Outstanding and Exercisable SARs (Detail) - Stock Appreciation Rights (SARs) [Member] $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2020 USD ($) $ / shares shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares | shares	51,589
Weighted Average Base Value | $ / shares	$ 30.64
Weighted Average Remaining Contractual Life (years)	1 year
Aggregate Intrinsic Value | $	$ 6.2