Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Amount, after accumulated amortization, of debt premium.

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Amount of Federal Home Loan Bank (FHLBank) advances to member financial institutions.

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Amount of the collateral pledged in support of federal home loan bank advances outstanding.

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The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Amount, excluding unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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Including the current and noncurrent portions, carrying value as of the balance sheet date of subordinated debt (with initial maturities beyond one year or beyond the operating cycle if longer). Subordinated debt places a lender in a lien position behind debt having a higher priority of repayment in liquidation of the entity's assets.

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BORROWINGS - Narrative (Details) - USD ($)				9 Months Ended		12 Months Ended
BORROWINGS - Narrative (Details) - USD ($)	Mar. 15, 2022	Apr. 01, 2020	Nov. 05, 2019	Sep. 30, 2022	Jul. 15, 2021	Dec. 31, 2018	Dec. 31, 2021	Oct. 05, 2020
Debt Instrument [Line Items]
Long-term borrowings				$ 370,056,000			$ 172,712,000
Long-term debt				1,416,343,000			313,798,000
FHLB availability based on pledged collateral				2,500,000,000			2,700,000,000
FHLB advances				840,000,000			0
Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Maximum borrowing capacity				3,300,000,000			3,900,000,000
Federal Home Loan Bank Advances \| Residential mortgage \| Asset pledged as collateral \| Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Maximum borrowing capacity				1,100,000,000			829,100,000
Federal Home Loan Bank Advances \| Commercial real estate loans \| Asset pledged as collateral \| Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Maximum borrowing capacity				3,600,000,000			3,100,000,000
Federal Home Loan Bank Advances \| Home equity lines of credit \| Asset pledged as collateral \| Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Maximum borrowing capacity				215,000,000			224,400,000
Federal Home Loan Bank Advances \| Multifamily loans \| Asset pledged as collateral \| Federal Home Loan Bank Advances
Debt Instrument [Line Items]
Maximum borrowing capacity				476,100,000			333,400,000
Federal Reserve and correspondent banks
Debt Instrument [Line Items]
Maximum borrowing capacity				734,700,000			509,400,000
Line of credit				0			0
Unsecured lines of credit, correspondent banks
Debt Instrument [Line Items]
Maximum borrowing capacity				$ 1,400,000,000			1,300,000,000
Subordinated Debt \| Fixed Floating Rate Subordinated Notes Due 2032
Debt Instrument [Line Items]
Aggregate principal amount	$ 200,000,000
Interest rate	3.875%			3.875%
Basis spread on variable rate	1.965%
Unamortized discount (premium) and debt issuance costs, net	$ 3,100,000
Subordinated Debt \| Fixed Floating Rate Subordinated Notes Due 2029
Debt Instrument [Line Items]
Interest rate			4.25%	4.25%
Basis spread on variable rate			2.62%
Unamortized discount (premium) and debt issuance costs, net			$ 2,900,000
Long-term borrowings			$ 175,000,000
Subordinated Debt \| WashingtonFirst Bankshares Inc
Debt Instrument [Line Items]
Interest rate								6.00%
Basis spread on variable rate					4.57%
Long-term borrowings						$ 25,000,000
Add: Purchase accounting premium						$ 2,200,000
Debt instrument, term						10 years
Subordinated Debt \| Revere acquisition
Debt Instrument [Line Items]
Interest rate		5.625%
Basis spread on variable rate				4.41%
Long-term borrowings		$ 31,000,000
Add: Purchase accounting premium		$ 200,000
Debt instrument, term		10 years
Retail Repurchase Agreements
Debt Instrument [Line Items]
Long-term debt				$ 91,300,000			141,100,000
Federal Funds Purchased
Debt Instrument [Line Items]
Long-term debt				$ 115,000,000			$ 0