Outstanding and Weighted Average Common Shares - Changes in Outstanding Common Shares (Detail) - shares shares in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Equity [Abstract]
Beginning balance (in shares)	307,000	304,900	291,400
Conversion of preferred stock (in shares)	0	0	11,600
Activity related to restricted stock awards, net (in shares)	700	1,000	900
Stock options exercised (in shares)	1,538	300	700
PSUs vested (in shares)	500	800	300
Ending balance (in shares)	309,700	307,000	304,900