LOANS AND LEASES - Age Analysis of Past Due Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 20,817,436	$ 14,896,943
Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	8,822,023	5,435,162
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	3,980,584	3,042,781
Commercial Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	238,724	196,636
Total Commercial Loans and Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	13,041,331	8,674,579
Direct Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,925,995	1,844,399
Residential Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	2,609,663	1,844,574
Indirect Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,431,273	1,196,313
Consumer Lines of Credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	1,769,376	1,301,200
Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	39,798	35,878
Originated Loans and Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	132,516	131,046
Non- Accrual	77,784	62,083
Current	14,437,180	12,416,941
Total Loans	14,569,696	12,547,987
Originated Loans and Leases [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	44,454	59,850
Originated Loans and Leases [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	10,278	9,113
Originated Loans and Leases [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	29,212	28,567
Non- Accrual	24,188	20,114
Current	4,874,584	4,067,250
Total Loans	4,903,796	4,095,817
Originated Loans and Leases [Member] | Commercial Real Estate [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5,023	8,452
Originated Loans and Leases [Member] | Commercial Real Estate [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1	1
Originated Loans and Leases [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	39,327	40,163
Non- Accrual	32,541	24,141
Current	3,119,870	2,671,723
Total Loans	3,159,197	2,711,886
Originated Loans and Leases [Member] | Commercial and Industrial [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,880	16,019
Originated Loans and Leases [Member] | Commercial and Industrial [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,906	3
Originated Loans and Leases [Member] | Commercial Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,492	4,403
Non- Accrual	1,199	3,429
Current	236,232	192,233
Total Loans	238,724	196,636
Originated Loans and Leases [Member] | Commercial Leases [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,293	973
Originated Loans and Leases [Member] | Commercial Leases [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	1
Originated Loans and Leases [Member] | Total Commercial Loans and Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	71,031	73,133
Non- Accrual	57,928	47,684
Current	8,230,686	6,931,206
Total Loans	8,301,717	7,004,339
Originated Loans and Leases [Member] | Total Commercial Loans and Leases [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	11,196	25,444
Originated Loans and Leases [Member] | Total Commercial Loans and Leases [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,907	5
Originated Loans and Leases [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	23,101	21,443
Non- Accrual	8,858	6,484
Current	1,734,729	1,743,814
Total Loans	1,757,830	1,765,257
Originated Loans and Leases [Member] | Direct Installment [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	10,139	10,573
Originated Loans and Leases [Member] | Direct Installment [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,104	4,386
Originated Loans and Leases [Member] | Residential Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	18,798	16,924
Non- Accrual	5,687	3,316
Current	1,885,822	1,429,852
Total Loans	1,904,620	1,446,776
Originated Loans and Leases [Member] | Residential Mortgages [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	10,518	10,594
Originated Loans and Leases [Member] | Residential Mortgages [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	2,593	3,014
Originated Loans and Leases [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	10,129	11,808
Non- Accrual	1,927	1,983
Current	1,420,982	1,184,302
Total Loans	1,431,111	1,196,110
Originated Loans and Leases [Member] | Indirect Installment [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	7,765	9,312
Originated Loans and Leases [Member] | Indirect Installment [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	437	513
Originated Loans and Leases [Member] | Consumer Lines of Credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	7,705	6,257
Non- Accrual	2,456	1,616
Current	1,126,915	1,093,370
Total Loans	1,134,620	1,099,627
Originated Loans and Leases [Member] | Consumer Lines of Credit [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,545	3,529
Originated Loans and Leases [Member] | Consumer Lines of Credit [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	704	1,112
Originated Loans and Leases [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,752	1,481
Non- Accrual	928	1,000
Current	38,046	34,397
Total Loans	39,798	35,878
Originated Loans and Leases [Member] | Other [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	291	398
Originated Loans and Leases [Member] | Other [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	533	83
Acquired Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	174,641	68,130
Non- Accrual	10,607	3,396
Current	6,378,527	2,430,340
Total Loans	6,247,740	2,348,956
Discount	(305,428)	(149,514)
Acquired Loans [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	75,839	24,210
Acquired Loans [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	88,195	40,524
Acquired Loans [Member] | Commercial Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	104,733	34,340
Non- Accrual	3,485	949
Current	4,019,956	1,384,752
Total Loans	3,918,227	1,339,345
Discount	(206,462)	(79,747)
Acquired Loans [Member] | Commercial Real Estate [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	36,343	9,501
Acquired Loans [Member] | Commercial Real Estate [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	64,905	23,890
Acquired Loans [Member] | Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	19,883	6,842
Non- Accrual	6,151	2,111
Current	845,806	353,494
Total Loans	821,387	330,895
Discount	(44,302)	(29,441)
Acquired Loans [Member] | Commercial and Industrial [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	8,764	1,789
Acquired Loans [Member] | Commercial and Industrial [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	4,968	2,942
Acquired Loans [Member] | Commercial Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	0	0
Acquired Loans [Member] | Total Commercial Loans and Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	124,616	41,182
Non- Accrual	9,636	3,060
Current	4,865,762	1,738,246
Total Loans	4,739,614	1,670,240
Discount	(250,764)	(109,188)
Acquired Loans [Member] | Total Commercial Loans and Leases [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	45,107	11,290
Acquired Loans [Member] | Total Commercial Loans and Leases [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	69,873	26,832
Acquired Loans [Member] | Direct Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5,192	3,661
Non- Accrual	0	0
Current	161,616	73,479
Total Loans	168,165	79,142
Discount	1,357	2,002
Acquired Loans [Member] | Direct Installment [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	3,471	2,317
Acquired Loans [Member] | Direct Installment [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1,721	1,344
Acquired Loans [Member] | Residential Mortgages [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	31,882	19,244
Non- Accrual	0	0
Current	715,366	416,561
Total Loans	705,043	397,798
Discount	(42,205)	(38,007)
Acquired Loans [Member] | Residential Mortgages [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	20,535	8,428
Acquired Loans [Member] | Residential Mortgages [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	11,347	10,816
Acquired Loans [Member] | Indirect Installment [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1	23
Non- Accrual	0	0
Current	18	96
Total Loans	162	203
Discount	143	84
Acquired Loans [Member] | Indirect Installment [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	0	19
Acquired Loans [Member] | Indirect Installment [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	1	4
Acquired Loans [Member] | Consumer Lines of Credit [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	12,950	4,020
Non- Accrual	971	336
Current	635,765	201,958
Total Loans	634,756	201,573
Discount	(13,959)	(4,405)
Acquired Loans [Member] | Consumer Lines of Credit [Member] | 30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	6,726	2,156
Acquired Loans [Member] | Consumer Lines of Credit [Member] | Equal to Greater than 90 Days Past Due and Still Accruing [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Past Due	5,253	1,528
Acquired Loans [Member] | Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Loans	$ 0	$ 0