Net Income Per Common Share - Basic and Diluted Net Income Per Common Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Earnings Per Share Reconciliation [Abstract]
Income available to common stockholders	$ 35,915	$ 42,520
Income available to common stockholders plus assumed exercises of stock options	$ 35,915	$ 42,520
Income available to common stockholders - Shares	32,666,916	32,756,852
Dilutive effect of stock options - Shares	648,417	651,264
Income available to common stockholders plus assumed exercises of stock options - Shares	33,315,333	33,408,116
Income available to common stockholders - Per Share Amount	$ 1.10	$ 1.30
Income available to common stockholders plus assumed exercises of stock options - Per Share Amount	$ 1.08	$ 1.27