EARNINGS PER SHARE (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Earnings Per Share Reconciliation [Abstract]
Basic									41,738	42,739	43,892
Dilutive effect of stock options and deferred stock compensation									261	277	424
Diluted									41,999	43,016	44,316
Net earnings	$ 53,993	$ 64,620	$ 31,018	$ 51,761	$ 89,408	$ 82,510	$ 80,072	$ 55,593	$ 201,392	$ 307,583	$ 275,749
Diluted earnings per share	$ 1.30	$ 1.55	$ 0.74	$ 1.21	$ 2.08	$ 1.92	$ 1.86	$ 1.29	$ 4.80	$ 7.15	$ 6.22
Basic earnings per share	$ 1.31	$ 1.56	$ 0.75	$ 1.22	$ 2.09	$ 1.93	$ 1.87	$ 1.30	$ 4.83	$ 7.20	$ 6.28