Summary of Significant Accounting Policies - Computation of Basic EPS to Dilutive EPS (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Earnings Per Share [Abstract]
Net earnings per share, basic, Net Earnings	$ 56,918	$ 37,232
Effect of stock options and stock grants, Net Earnings	0	0
Net earnings per share, diluted, Net Earnings	$ 56,918	$ 37,232
Net earnings per share, basic, Weighted Average Shares	142,146,275	142,118,864
Effect of stock options and stock grants, Weighted Average Shares	856,383	616,344
Net earnings per share, diluted, Weighted Average Shares	143,002,658	142,735,208
Net earnings per share, basic, Per Share Amount	$ 0.40	$ 0.26
Effect of stock options and stock grants, Per Share Amount	0	0
Net earnings per share, diluted, Per Share Amount	$ 0.40	$ 0.26