ALLOWANCE FOR LOAN AND LEASE LOSSES - Changes in Allowance for Loan and Lease Losses (Detail) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2017		Jun. 30, 2016	Jun. 30, 2017		Jun. 30, 2016	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	$ 203,231		$ 238,125	$ 205,603		$ 240,710
Charge-offs	(55,488)		(28,366)	(88,382)		(54,901)
Recoveries	7,646		3,709	12,726		6,606
Provision For Loan Lease And Other Losses	18,096		20,986	43,538		42,039
Ending balance	173,485		234,454	173,485		234,454
Balance at end of period	40,794		86,372	40,794		86,372
Allowance for loan losses Purchased Credit Impaired	9,446		6,857	9,446		6,857
Ending balance: general allowance	123,245		141,225	123,245		141,225
Ending balance	8,861,176		8,870,747	8,861,176		8,870,747
Ending balance: impaired loans	735,625		953,774	735,625		953,774	$ 807,198	$ 887,905	$ 917,591	$ 806,509
Ending balance: purchased credit-impaired loans	160,368		169,690	160,368		169,690
Ending balance: loans with general allowance	7,965,183		7,747,283	7,965,183		7,747,283
Purchased Credit Impaired [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses Purchased Credit Impaired	9,446	[1]	6,857	9,446	[1]	6,857
Residential Mortgage [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	35,775		38,548	33,980		39,570
Charge-offs	(6,967)		(11,532)	(15,192)		(18,838)
Recoveries	891		841	1,640		1,187
Provision For Loan Lease And Other Losses	10,888		11,098	20,159		17,036
Ending balance	40,587		38,955	40,587		38,955
Balance at end of period	13,786		11,972	13,786		11,972
Ending balance: general allowance	17,727		20,345	17,727		20,345
Ending balance	3,282,307		3,323,844	3,282,307		3,323,844
Ending balance: impaired loans	428,711		452,280	428,711		452,280
Ending balance: purchased credit-impaired loans	156,202		166,556	156,202		166,556
Ending balance: loans with general allowance	2,697,394		2,705,008	2,697,394		2,705,008
Residential Mortgage [Member] | Purchased Credit Impaired [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses Purchased Credit Impaired	9,074	[1]	6,638	9,074	[1]	6,638
Commercial Mortgage [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	68,468		68,744	57,261		68,211
Charge-offs	(30,495)		(1,437)	(31,857)		(2,012)
Recoveries	78		33	108		79
Provision For Loan Lease And Other Losses	525		2,459	13,064		3,521
Ending balance	38,576		69,799	38,576		69,799
Balance at end of period	8,330		40,071	8,330		40,071
Ending balance: general allowance	29,874		29,509	29,874		29,509
Ending balance	1,611,730		1,523,676	1,611,730		1,523,676
Ending balance: impaired loans	140,621		211,348	140,621		211,348
Ending balance: purchased credit-impaired loans	4,166		3,134	4,166		3,134
Ending balance: loans with general allowance	1,466,943		1,309,194	1,466,943		1,309,194
Commercial Mortgage [Member] | Purchased Credit Impaired [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses Purchased Credit Impaired	372	[1]	219	372	[1]	219
Commercial And Industrial Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	45,970		71,098	61,953		68,768
Charge-offs	(6,378)		(1,914)	(18,430)		(5,673)
Recoveries	4,624		676	5,499		956
Provision For Loan Lease And Other Losses	(2,134)		(71)	(6,940)		5,738
Ending balance	42,082		69,789	42,082		69,789
Balance at end of period	10,788		27,750	10,788		27,750
Ending balance: general allowance	31,294		42,039	31,294		42,039
Ending balance	2,116,756		2,133,623	2,116,756		2,133,623
Ending balance: impaired loans	74,902		197,368	74,902		197,368
Ending balance: purchased credit-impaired loans	0		0	0		0
Ending balance: loans with general allowance	2,041,854		1,936,255	2,041,854		1,936,255
Commercial And Industrial Loans [Member] | Purchased Credit Impaired [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses Purchased Credit Impaired	0	[1]	0	0	[1]	0
Construction Loans [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	3,886		3,013	2,562		3,519
Charge-offs	(595)		(513)	(658)		(604)
Recoveries	133		144	578		161
Provision For Loan Lease And Other Losses	312		103	1,254		(329)
Ending balance	3,736		2,747	3,736		2,747
Balance at end of period	2,374		1,114	2,374		1,114
Ending balance: general allowance	1,362		1,633	1,362		1,633
Ending balance	122,093		137,406	122,093		137,406
Ending balance: impaired loans	50,557		49,216	50,557		49,216
Ending balance: purchased credit-impaired loans	0		0	0		0
Ending balance: loans with general allowance	71,536		88,190	71,536		88,190
Construction Loans [Member] | Purchased Credit Impaired [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses Purchased Credit Impaired	0	[1]	0	0	[1]	0
Consumer Loan [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Beginning balance	49,132		56,722	49,847		60,642
Charge-offs	(11,053)		(12,970)	(22,245)		(27,774)
Recoveries	1,920		2,015	4,901		4,223
Provision For Loan Lease And Other Losses	8,505		7,397	16,001		16,073
Ending balance	48,504		53,164	48,504		53,164
Balance at end of period	5,516		5,465	5,516		5,465
Ending balance: general allowance	42,988		47,699	42,988		47,699
Ending balance	1,728,290		1,752,198	1,728,290		1,752,198
Ending balance: impaired loans	40,834		43,562	40,834		43,562
Ending balance: purchased credit-impaired loans	0		0	0		0
Ending balance: loans with general allowance	1,687,456		1,708,636	1,687,456		1,708,636
Consumer Loan [Member] | Purchased Credit Impaired [Member]
Financing Receivable Allowance For Credit Losses [Line Items]
Allowance for loan losses Purchased Credit Impaired	$ 0	[1]	$ 0	$ 0	[1]	$ 0

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