Stock Awards - Stock-based Award Activity (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Vesting Based on Service [Member]
Employee Restricted Equity Awards Vesting Activity [Line Items]
Nonvested awards at beginning of the year, Shares	1,057,054	1,122,440
Awarded, Shares	651,113	635,855
Vested, Shares	(781,076)	(699,215)
Forfeited, Shares	(4,137)	(2,026)
Nonvested awards at end of year, Shares	922,954	1,057,054
Nonvested awards at beginning of the year, Weighted Average Value at Award Date	$ 18.79	$ 17.11
Awarded, Weighted Average Value at Award Date	20.83	19.65
Vested, Weighted Average Value at Award Date	18.77	16.80
Forfeited, Weighted Average Value at Award Date	18.69	18.40
Nonvested awards at end of year, Weighted Average Value at Award Date	$ 20.26	$ 18.79
Vesting Based on Market/Performance Conditions [Member]
Employee Restricted Equity Awards Vesting Activity [Line Items]
Nonvested awards at beginning of the year, Shares	5,086,983	5,481,155
Awarded, Shares	1,957,802	1,800,898
Vested, Shares	(1,551,482)	(2,193,906)
Forfeited, Shares	(15,767)	(1,164)
Nonvested awards at end of year, Shares	5,477,536	5,086,983
Nonvested awards at beginning of the year, Weighted Average Value at Award Date	$ 14.41	$ 11.66
Awarded, Weighted Average Value at Award Date	17.94	19.42
Vested, Weighted Average Value at Award Date	13.73	11.35
Forfeited, Weighted Average Value at Award Date	16.72	18.22
Nonvested awards at end of year, Weighted Average Value at Award Date	$ 15.86	$ 14.41