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Stock-Based Compensation - Summarizes Information of Performance Share Awards (Detail) - Performance Awards
12 Months Ended
Dec. 31, 2020
$ / shares
shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]  
Non-vested at December 31, 2019 | shares 555,657
Granted | shares 192,958
Vested | shares (60,048)
Forfeited | shares (112,108)
Non-vested at December 31, 2020 | shares 576,459
Non-vested at December 31, 2019 | $ / shares $ 53.71
Granted | $ / shares 68.15
Vested | $ / shares 58.08
Forfeited | $ / shares 56.32
Non-vested at December 31, 2020 | $ / shares $ 57.54