LOAN PORTFOLIO - Loan Restructuring and Effect on Allowance for Loan and Lease Losses (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans and Leases Receivable Disclosure [Abstract]
Beginning balance	$ 231,843	$ 205,603	$ 240,710
Provision for loan and lease losses	59,253	144,254	86,733
Ending balance	196,362	231,843	205,603
Entity Loan Modification Program [Member]
Financing Receivable, Additional Disclosures [Abstract]
Beginning Balance of TDRs	587,219	647,048	661,591
New TDRs loan splits	171,857	93,837	84,942
Paid-off and partial payments	(99,373)	(48,974)	(57,935)
Ending balance of TDRs	582,647	587,219	647,048
Entity Loan Modification Program [Member] | AB Note Restructure Workout Strategy [Member]
Financing Receivable, Additional Disclosures [Abstract]
Beginning Balance of TDRs	35,577	36,971	39,329
New TDRs loan splits	32,104	0	0
Paid-off and partial payments	(33,841)	(1,394)	(2,358)
Ending balance of TDRs	33,840	35,577	36,971
Loans and Leases Receivable Disclosure [Abstract]
Beginning balance	3,846	5,141	862
Provision for loan and lease losses	(10,789)	(1,295)	4,279
Net loan loss recoveries	7,416	0	0
Ending balance	$ 473	$ 3,846	$ 5,141