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LOANS AND ALLOWANCE FOR LOAN AND LEASE LOSSES (Narrative) (Details)		3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 26, 2025 USD ($)	Jun. 30, 2025 USD ($)	Jun. 30, 2024 USD ($)	Jun. 30, 2025 USD ($) segment	Jun. 30, 2024 USD ($)	Dec. 31, 2024 USD ($)	Apr. 01, 2025 USD ($)	Mar. 31, 2025 USD ($)	Mar. 31, 2024 USD ($)	Dec. 31, 2023 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gain on CRE loan sale				$ 15,720,000	$ 0
Nonaccrual loans, interest income		$ 0	$ 0	0	0
Loans under modified terms		18,091,000	23,920,000	20,232,000	24,096,000
Amortized Cost		18,091,000	23,920,000	20,232,000	24,096,000
Total Allowance for credit losses		315,574,000	158,131,000	315,574,000	158,131,000	$ 178,644,000		$ 193,796,000	$ 136,190,000	$ 132,182,000
Unfunded commitments on loans modified and designated as TLMs		0		0
TLM loans that went into default		0	0	0	0
TLMs that are past due		0	0	$ 0	0
Number of operating segments \| segment				2
Loans held for investment, accrued interest receivable		107,200,000		$ 107,200,000		73,700,000
Financing Receivable Accrued Interest After Allowance For Credit Loss Statement Of Financial Position Extensible List Not Disclosed (Flag)				true
Revolving loans converted to term				$ 0		0
Sandy Spring
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid principle balance of CRE loans acquired	$ 2,000,000,000
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total Allowance for credit losses		$ 257,403,000	$ 131,139,000	$ 257,403,000	$ 131,139,000	$ 148,887,000		$ 162,908,000	$ 110,528,000	$ 105,896,000
CRE \| Sandy Spring
Accounts, Notes, Loans and Financing Receivable [Line Items]
LHFS							$ 1,839,968,000
Gain on CRE loan sale	$ 15,700,000