LOANS AND LEASES RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES ON LOANS AND LEASES - Schedule of Allowance for Credit Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	$ 147,418	$ 132,436	$ 136,775	$ 135,311	$ 135,311
Allowance for credit losses on FDIC PCD loans, net of charge-offs			1,000
Charge-offs	(17,500)	(21,224)	(55,425)	(66,775)	(84,465)
Recoveries	2,129	4,180	9,795	13,052
Provision (benefit) for credit losses on loans and leases	19,762	17,766	59,664	51,570
Ending balance	151,809	133,158	151,809	133,158	136,775
Commercial and industrial, including specialized lending
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	36,262	23,721	29,379	23,503	23,503
Allowance for credit losses on FDIC PCD loans, net of charge-offs			1,000
Charge-offs	(2,383)	(6,538)	(12,886)	(19,282)
Recoveries	203	1,482	3,604	4,889
Provision (benefit) for credit losses on loans and leases	313	6,526	13,298	16,081
Ending balance	34,395	25,191	34,395	25,191	29,379
Allowance for credit losses			1,000
Multifamily
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	20,864	20,652	18,511	16,343	16,343
Allowance for credit losses on FDIC PCD loans, net of charge-offs			0
Charge-offs	0	(2,167)	(3,834)	(4,073)
Recoveries	0	0	0	0
Provision (benefit) for credit losses on loans and leases	(891)	(395)	5,296	5,820
Ending balance	19,973	18,090	19,973	18,090	18,511
Commercial real estate owner occupied
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	12,514	8,431	10,755	9,882	9,882
Allowance for credit losses on FDIC PCD loans, net of charge-offs			0
Charge-offs	(335)	(4)	(771)	(26)
Recoveries	0	0	9	0
Provision (benefit) for credit losses on loans and leases	(1,188)	2,486	998	1,057
Ending balance	10,991	10,913	10,991	10,913	10,755
Commercial real estate non-owner occupied
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	20,679	17,966	17,405	16,859	16,859
Allowance for credit losses on FDIC PCD loans, net of charge-offs			0
Charge-offs	(3,073)	0	(3,073)	0
Recoveries	0	0	0	0
Provision (benefit) for credit losses on loans and leases	2,178	(663)	5,452	444
Ending balance	19,784	17,303	19,784	17,303	17,405
Construction
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	2,160	1,856	1,250	1,482	1,482
Allowance for credit losses on FDIC PCD loans, net of charge-offs			0
Charge-offs	0	0	0	0
Recoveries	0	3	6	10
Provision (benefit) for credit losses on loans and leases	(182)	(253)	722	114
Ending balance	1,978	1,606	1,978	1,606	1,250
Residential real estate
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	6,331	5,884	5,968	6,586	6,586
Allowance for credit losses on FDIC PCD loans, net of charge-offs			0
Charge-offs	(39)	(19)	(40)	(38)
Recoveries	14	40	19	61
Provision (benefit) for credit losses on loans and leases	39	(68)	398	(772)
Ending balance	6,345	5,837	6,345	5,837	5,968
Manufactured housing
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	3,721	4,094	3,829	4,239	4,239
Allowance for credit losses on FDIC PCD loans, net of charge-offs			0
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Provision (benefit) for credit losses on loans and leases	(213)	(13)	(321)	(158)
Ending balance	3,508	4,081	3,508	4,081	3,829
Installment
Financing Receivable, Allowance for Credit Loss [Roll Forward]
Beginning balance	44,887	49,832	49,678	56,417	56,417
Allowance for credit losses on FDIC PCD loans, net of charge-offs			0
Charge-offs	(11,670)	(12,496)	(34,821)	(43,356)
Recoveries	1,912	2,655	6,157	8,092
Provision (benefit) for credit losses on loans and leases	19,706	10,146	33,821	28,984
Ending balance	$ 54,835	$ 50,137	$ 54,835	$ 50,137	$ 49,678