NATURE OF BUSINESS AND SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Transition Adjustment of ASC 326 (Detail) - USD ($) $ in Thousands			12 Months Ended
	Jan. 01, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss		$ 0	$ 8,845
Financing Receivable Allowance For Credit Losses		155,139	385,887	$ 196,362	$ 231,843
Off-Balance Sheet, Credit Loss, Liability		0	5,105	412	676
Pre-tax effect in beginning retained eaarnings		(155,139)
Balance sheet reclassification			(230,800)
Accounting Standards Update 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	$ 8,134
Financing Receivable Allowance For Credit Losses	236,304
Off-Balance Sheet, Credit Loss, Liability	3,922
Pre-tax effect in beginning retained eaarnings	(248,360)
Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt Securities, Held-to-maturity, Allowance for Credit Loss	8,134
Financing Receivable Allowance For Credit Losses	81,165
Off-Balance Sheet, Credit Loss, Liability	3,922
Pre-tax effect in beginning retained eaarnings	(93,221)
Balance sheet reclassification	434
Tax effect	31,333
Cumulative Effect on Retained Earnings, Net of Tax	(62,322)
Residential Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses		44,806	120,311	50,794	58,975
Residential Portfolio Segment [Member] | Accounting Standards Update 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses	94,643
Residential Portfolio Segment [Member] | Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses	49,837
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses		15,198	37,944	32,546	48,871
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member] | Accounting Standards Update 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses	29,929
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member] | Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses	14,731
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses		39,194	109,342	55,581	48,493
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Accounting Standards Update 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses	19,888
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses	(19,306)
Commercial Portfolio Segment [Member] | Construction Loans [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses		2,370	5,380	3,592	4,522
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Accounting Standards Update 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses	3,167
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses	797
Consumer Portfolio Segment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses		$ 53,571	$ 112,910	$ 53,849	$ 70,982
Consumer Portfolio Segment [Member] | Accounting Standards Update 2016-13 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses	88,677
Consumer Portfolio Segment [Member] | Accounting Standards Update 2016-13 [Member] | Cumulative Effect, Period of Adoption, Adjustment [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Financing Receivable Allowance For Credit Losses	$ 35,106