SEGMENT INFORMATION - Reconciliation of Reportable Segment Financial Information (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Net Income (Loss):
Total before tax	$ 116,323	$ 239,372	$ 190,638
Income tax (benefit) expense	(14,050)	(71,995)	10,970
Net income	102,273	167,377	201,608
Segment Reconciling Items [Member]
Net Income (Loss):
Segment income	281,699	365,237	298,185
Other operating expenses	(165,376)	(125,865)	(107,547)
Total before tax	116,323	239,372	190,638
Income tax (benefit) expense	14,050	71,995	(10,970)
Net income	102,273	167,377	201,608
Average assets:
Total average earning assets for segments	14,201,505	11,497,408	11,265,470
Average non-earning assets	1,031,141	954,726	940,731
Total consolidated average assets	$ 15,232,646	$ 12,452,134	$ 12,206,201