LOANS HELD FOR INVESTMENT - Corporation's Aging of Loans Held for Investment Portfolio (Parenthetical) (Detail) - USD ($)	Dec. 31, 2021	Dec. 31, 2020
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 11,060,658,000	$ 11,777,289,000
Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,113,918,000	9,788,106,000
Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,946,740,000	1,989,183,000
30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	44,202,000	48,129,000
30-59 Days Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	43,709,000	47,143,000
30-59 Days Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	493,000	986,000
Current [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	315,728,000	498,303,000
Current [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	304,525,000	477,726,000
Current [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	11,203,000	20,577,000
Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	10,744,930,000	11,278,986,000
Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	8,809,393,000	9,310,380,000
Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 1,935,537,000	1,968,606,000
Residential Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, Threshold Period Past Due, Writeoff	180 days
Financing Receivable, before Allowance for Credit Loss	$ 2,978,895,000	3,521,954,000
Residential Portfolio Segment [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,549,573,000	3,002,203,000
Residential Portfolio Segment [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	429,322,000	519,751,000
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,853,503,000	3,371,220,000
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,424,921,000	2,852,639,000
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	428,582,000	518,581,000
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | 30-59 Days Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | 30-59 Days Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	115,392,000	228,478,000
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Current [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	106,132,000	210,819,000
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Current [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	9,260,000	17,659,000
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,738,111,000	3,142,742,000
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,318,789,000	2,641,820,000
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	419,322,000	500,922,000
Residential Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Less Than Two Payments In Arrears [Member] | 30-59 Days Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,900,000	6,600,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	125,392,000	150,734,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	124,652,000	149,564,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	740,000	1,170,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | 30-59 Days Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | 30-59 Days Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Past Due, 15 Months Delinquent [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	46,600,000	57,900,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Past Due, 15 Months Delinquent [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	46,600,000	57,900,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Past Due, 15 Months Delinquent [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	67,870,000	101,466,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Current [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	67,749,000	101,216,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Current [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	121,000	250,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	57,522,000	49,268,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	56,903,000	48,348,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	619,000	920,000
Residential Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Less Than Two Payments In Arrears [Member] | 30-59 Days Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		200,000
Residential Portfolio Segment [Member] | GNMA [Member] | Repurchase Option Program [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	7,200,000	10,700,000
Residential Portfolio Segment [Member] | GNMA [Member] | Unconditional Option To Repurchase [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	7,200,000	10,700,000
Residential Portfolio Segment [Member] | GNMA [Member] | Unconditional Option To Repurchase [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	7,200,000	10,700,000
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,167,469,000	2,230,602,000
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,702,231,000	1,853,224,000
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	465,238,000	377,378,000
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,402,000	5,071,000
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | 30-59 Days Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,402,000	5,071,000
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | 30-59 Days Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	38,094,000	44,522,000
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Current [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	38,094,000	44,522,000
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Current [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,129,375,000	2,186,080,000
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	1,664,137,000	1,808,702,000
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member] | Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	465,238,000	377,378,000
Commercial Portfolio Segment [Member] | Construction Loans [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	138,999,000	212,500,000
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	43,133,000	85,016,000
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	95,866,000	127,484,000
Commercial Portfolio Segment [Member] | Construction Loans [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	18,000	0
Commercial Portfolio Segment [Member] | Construction Loans [Member] | 30-59 Days Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	18,000	0
Commercial Portfolio Segment [Member] | Construction Loans [Member] | 30-59 Days Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Current [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,682,000	12,990,000
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Current [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,682,000	12,990,000
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Current [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	0	0
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	136,317,000	199,510,000
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	40,451,000	72,026,000
Commercial Portfolio Segment [Member] | Construction Loans [Member] | Past Due [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	95,866,000	127,484,000
Commercial Portfolio Segment [Member] | Less Than Two Payments In Arrears [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		100,000
Commercial Portfolio Segment [Member] | Less Than Two Payments In Arrears [Member] | 30-59 Days Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss		100,000
Commercial Portfolio Segment [Member] | Less Than Two Payments In Arrears [Member] | Mortgage Receivable [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	700,000	5,000,000.0
Commercial Portfolio Segment [Member] | Less Than Two Payments In Arrears [Member] | Mortgage Receivable [Member] | 30-59 Days Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	700,000	5,000,000.0
Commercial Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Less Than Two Payments In Arrears [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	66,000,000.0	111,800,000
Commercial Portfolio Segment [Member] | Conventional residential mortgage loans [Member] | Less Than Two Payments In Arrears [Member] | 30-59 Days Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	63,100,000	105,200,000
Commercial Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Less Than Two Payments In Arrears [Member] | 30-59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,100,000	6,100,000
Commercial Portfolio Segment [Member] | FHA/VA government-guaranteed loans [Member] | Less Than Two Payments In Arrears [Member] | 30-59 Days Past Due [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	6,100,000	5,900,000
Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,888,044,000	2,609,643,000
Consumer Portfolio Segment [Member] | Puerto Rico and Virgin Islands regions [Member]
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	2,872,384,000	2,582,932,000
Consumer Portfolio Segment [Member] | Florida region [Member}
Financing Receivable, Past Due [Line Items]
Financing Receivable, before Allowance for Credit Loss	$ 15,660,000	$ 26,711,000