LOAN PORTFOLIO - Consumer Credit Exposure (Detail) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 8,996,816	$ 8,858,123	$ 8,695,890
Residential Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	3,126,562	3,163,208	3,267,868
Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,015,292	1,944,713	1,734,596
Other Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,984,907	3,016,003
Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	676,409	664,701
Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	986,606	946,476
Finance leases loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	352,277	333,536
FHA/VA government-guaranteed loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	141,655	147,205
PCI loans
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	144,443	146,640	155,281	$ 158,174
PCI loans | Residential Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	140,979	143,176	151,067
PCI loans | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0	0	0
PCI loans | Other Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	140,979	143,176
PCI loans | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0	0
PCI loans | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0	0
PCI loans | Finance leases loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0	0
PCI loans | FHA/VA government-guaranteed loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	0	0
Performing Financing Receivable [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	8,119,502	7,951,214	7,794,329
Performing Financing Receivable [Member] | Residential Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,591,848	2,616,300	2,699,191
Performing Financing Receivable [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,986,864	1,913,387	$ 1,699,897
Performing Financing Receivable [Member] | Other Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	2,711,879	2,725,540
Performing Financing Receivable [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	670,616	656,836
Performing Financing Receivable [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	976,078	935,264
Performing Financing Receivable [Member] | Finance leases loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	351,268	332,207
Performing Financing Receivable [Member] | FHA/VA government-guaranteed loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	141,655	147,205
Nonaccrual [Member] | Other Loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	132,049	147,287
Nonaccrual [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	5,793	7,865
Nonaccrual [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	10,528	11,212
Nonaccrual [Member] | Finance leases loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	1,009	1,329
Nonaccrual [Member] | FHA/VA government-guaranteed loans [Member] | Residential Portfolio Segment [Member]
Financing Receivable Recorded Investment [Line Items]
Loans and Leases Receivable, Gross	$ 0	$ 0