LOANS HELD FOR INVESTMENT - Selected Information on TDRs includes Recorded Investment by Loan Class and Modification Type (Detail) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	$ 2,559	$ 2,180	$ 40,135
Residential Portfolio Segment [Member] | Conventional Loan [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	$ 464	$ 880	1,679
Percentage of Total by Portfolio Classes	0.02%	0.03%
Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	$ 13	$ 40	375
Percentage of Total by Portfolio Classes	0.00%	0.00%
Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	$ 0	$ 0	32,384
Percentage of Total by Portfolio Classes	0.00%	0.00%
Construction loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	$ 0	$ 0	0
Percentage of Total by Portfolio Classes	0.00%	0.00%
Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	$ 1,335	$ 711	3,271
Percentage of Total by Portfolio Classes	0.07%	0.04%
Personal Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	$ 28	$ 42	340
Percentage of Total by Portfolio Classes	0.01%	0.01%
Credit Card Receivables [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	$ 548	$ 289	1,553
Percentage of Total by Portfolio Classes	0.17%	0.09%
Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	$ 171	$ 218	$ 533
Percentage of Total by Portfolio Classes	0.11%	0.15%
Forbearance [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	$ 0	$ 0
Forbearance [Member] | Residential Portfolio Segment [Member] | Conventional Loan [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Forbearance [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Forbearance [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Forbearance [Member] | Construction loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Forbearance [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Forbearance [Member] | Personal Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Forbearance [Member] | Credit Card Receivables [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Forbearance [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Payment Plan [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Payment Plan [Member] | Residential Portfolio Segment [Member] | Conventional Loan [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Payment Plan [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Payment Plan [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Payment Plan [Member] | Construction loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Payment Plan [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Payment Plan [Member] | Personal Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Payment Plan [Member] | Credit Card Receivables [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Payment Plan [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Trial Modification [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	464	332
Trial Modification [Member] | Residential Portfolio Segment [Member] | Conventional Loan [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	464	332
Trial Modification [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Trial Modification [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Trial Modification [Member] | Construction loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Trial Modification [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Trial Modification [Member] | Personal Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Trial Modification [Member] | Credit Card Receivables [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Trial Modification [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Interest Rate [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	570	289
Interest Rate [Member] | Residential Portfolio Segment [Member] | Conventional Loan [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Interest Rate [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	13	0
Interest Rate [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Interest Rate [Member] | Construction loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Interest Rate [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Interest Rate [Member] | Personal Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	9	0
Interest Rate [Member] | Credit Card Receivables [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	548	289
Interest Rate [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Term Extension [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	328	682
Term Extension [Member] | Residential Portfolio Segment [Member] | Conventional Loan [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	433
Term Extension [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Term Extension [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Term Extension [Member] | Construction loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Term Extension [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	174	89
Term Extension [Member] | Personal Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	14	28
Term Extension [Member] | Credit Card Receivables [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Term Extension [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	140	132
Combination Of Interest Rate Reduction And Term Extension [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	137	227
Combination Of Interest Rate Reduction And Term Extension [Member] | Residential Portfolio Segment [Member] | Conventional Loan [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	115
Combination Of Interest Rate Reduction And Term Extension [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Combination Of Interest Rate Reduction And Term Extension [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Combination Of Interest Rate Reduction And Term Extension [Member] | Construction loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Combination Of Interest Rate Reduction And Term Extension [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	125	38
Combination Of Interest Rate Reduction And Term Extension [Member] | Personal Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	5	14
Combination Of Interest Rate Reduction And Term Extension [Member] | Credit Card Receivables [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Combination Of Interest Rate Reduction And Term Extension [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	7	60
Other Loan Modifications [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	1,060	650
Other Loan Modifications [Member] | Residential Portfolio Segment [Member] | Conventional Loan [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Other Loan Modifications [Member] | Commercial Portfolio Segment [Member] | Commercial And Industrial Sector [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	40
Other Loan Modifications [Member] | Commercial Portfolio Segment [Member] | Mortgage Receivable [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Other Loan Modifications [Member] | Construction loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Other Loan Modifications [Member] | Auto loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	1,036	584
Other Loan Modifications [Member] | Personal Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Other Loan Modifications [Member] | Credit Card Receivables [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	0	0
Other Loan Modifications [Member] | Other Loans [Member] | Consumer Portfolio Segment [Member]
Financing Receivable Modifications [Line Items]
Loans modified to borrowers experiencing financial difficulty	$ 24	$ 26