LOAN PORTFOLIO - Activity for Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019		Mar. 31, 2018
Impaired Loans:
Balance at beginning of period	$ 760,269		$ 790,308
Loans determined impaired during the period	10,702		61,408
Charge-offs	(13,421)	[1]	(17,213)
Loans sold, net charge-offs	0		(4,121)
Increases to existing impaired loans	1,253		6,998
Foreclosures	(7,984)		(11,675)
Loans no longer considered impaired	(152)		(1,507)
Loans transferred to held for sale	0		(57,213)
Paid in full or partial payments	(17,796)		(20,705)
Balance at end of period	$ 732,871		$ 746,280

[1] The first quarter of 2018 includes charge-offs totaling $9.7 million associated with $57.2 million in nonaccrual loans transferred to held for sale.