Stock-Based Compensation - Shares Issued in Connection with Stock Compensation Awards (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Share-based Payment Arrangement [Abstract]
New shares issued from available authorized shares	0	0	0	0
Shares issued from available treasury stock	114,252	77,303	628,076	143,523
Total	114,252	77,303	628,076	143,523
Proceeds from stock option exercises	$ 7,285	$ 3,383	$ 36,682	$ 4,846

Treasury Shares Issued Related To Stock Option Exercises

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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Number of shares issued under share-based payment arrangement.

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Number of shares issued during the period as a result of an employee stock purchase plan.

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