Earnings Per Share - Reconciliation of Numerator and Denominator of Basic Earnings Per Share with that of Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Earnings Per Share [Abstract]
Distributed earnings allocated to common stock	$ 48,288	$ 45,085	$ 97,345	$ 90,153
Undistributed earnings allocated to common stock	47,071	49,478	79,462	111,007
Net earnings allocated to common shareholders	$ 95,359	$ 94,563	$ 176,807	$ 201,160
Average common shares outstanding	134,623,061	128,750,851	135,336,729	128,693,616
Equivalents from stock options	240,589	283,137	297,669	252,664
Average diluted shares outstanding	134,863,650	129,033,988	135,634,398	128,946,280
Earnings per basic common share	$ 0.71	$ 0.73	$ 1.31	$ 1.56
Earnings per diluted common share	$ 0.71	$ 0.73	$ 1.3	$ 1.56