Stock Options and Other Equity-Based Incentive Instruments - Information about Options (Detail) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Information about Options
Intrinsic value of options exercised	$ 403	$ 4,169	$ 2,109
Fair value of options that vested	0	0	75
Total compensation costs for options recognized in expense	0	0	75
Excess tax benefit recognized in income	0	0	22
ASU 2016-09
Information about Options
Excess tax benefit recognized in income	$ 0	$ 1,233	$ 623

Amount of expense for award under share-based payment arrangement. Excludes amount capitalized.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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Fair value of options vested. Excludes equity instruments other than options, for example, but not limited to, share units, stock appreciation rights, restricted stock.

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