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Stock Based Compensation - Summary of Changes in Non Vested Shares of Restricted Stock (Detail) - $ / shares
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]      
Non-vested shares, beginning balance 4,022,409 4,026,110 3,913,634
Granted shares 1,526,825 1,390,914 1,585,870
Vested shares (1,737,304) (1,116,329) (874,665)
Forfeited shares (350,022) (278,286) (598,729)
Non-vested shares, ending balance 3,461,908 4,022,409 4,026,110
Non-vested, weighted average grant-date fair value, beginning of period $ 38.44 $ 35.63 $ 37.12
Granted, weighted average grant-date fair value 43.21 52.71 44.58
Vested, weighted average grant-date fair value 24.19 46.19 57.36
Forfeited, weighted average grant-date fair value 47.13 38.06 37.34
Non-vested, weighted average grant-date fair value, end of period $ 46.82 $ 38.44 $ 35.63