Note 7 - Investment Securities

3 Months Ended

Mar. 31, 2024

Notes to Financial Statements

Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]

7. Investment Securities

The following tables set forth the amortized cost, gross unrealized gains, gross unrealized losses, and fair value of securities available-for-sale ("AFS") as of March 31, 2024, and December 31, 2023

	March 31, 2024
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities AFS
U.S. treasury securities	$	541,914	$	4	$	120	$	541,798
U.S. government agency entities		12,123		61		126		12,058
U.S. government sponsored entities		59,785		—		40		59,745
Mortgage-backed securities		871,231		63		117,132		754,162
Collateralized mortgage obligations		30,494		—		3,296		27,198
Corporate debt securities		268,368		34		10,196		258,206
Total	$	1,783,915	$	162	$	130,910	$	1,653,167

	December 31, 2023
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities AFS
U.S. treasury securities	$	495,167	$	153	$	20	$	495,300
U.S. government agency entities		48,282		117		230		48,169
Mortgage-backed securities		892,942		223		106,442		786,723
Collateralized mortgage obligations		31,238		—		3,194		28,044
Corporate debt securities		258,451		22		12,139		246,334
Total	$	1,726,080	$	515	$	122,025	$	1,604,570

As of March 31, 2024, the amortized cost of securities AFS excluded accrued interest receivables of $4.8 million, which are included in accrued interest receivable on the Consolidated Balance Sheets. For the Company’s accounting policy related to securities AFS accrued interest receivable, see Note 1 - Summary of Significant Accounting Policies – Securities Available for Sale – Allowance for Credit Losses on Available for Sale Securities to the Consolidated Financial Statements in the Company’s 2023 Form 10-K.

The amortized cost and fair value of securities AFS as of March 31, 2024, by contractual maturities, are set forth in the tables below. Actual maturities may differ from contractual maturities because borrowers may have the right to call or repay obligations with or without call or repayment penalties.  

	March 31, 2024
	Securities AFS
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	661,864	$	661,135
Due after one year through five years		207,407		198,023
Due after five years through ten years		140,147		131,192
Due after ten years		774,497		662,817
Total	$	1,783,915	$	1,653,167

Equity Securities - The Company recognized an unrealized net loss of $9.0 million for the three months ended March 31, 2024, due to a decrease in fair value of equity investments with readily determinable fair values compared to a net gain of $4.9 million for the three months ended March 31, 2023. Equity securities were $31.4 million and $40.4 million as of March 31, 2024, and December 31, 2023, respectively.

The following tables set forth the gross unrealized losses and related fair value of the Company’s investment portfolio, aggregated by investment category and the length of time that individual security has been in a continuous unrealized loss position, as of  March 31, 2024, and  December 31, 2023:

	March 31, 2024
	Less than 12 Months				12 Months or Longer				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Securities AFS
U.S. treasury securities	$	392,376	$	120	$	—	$	—	$	392,376	$	120
U.S. government agency entities		1,471		2		2,524		124		3,995		126
U.S. government sponsored entities		59,745		40		—		—		59,745		40
Mortgage-backed securities		16,923		87		736,362		117,045		753,285		117,132
Collateralized mortgage obligations		—		—		27,198		3,296		27,198		3,296
Corporate debt securities		54,531		469		168,641		9,727		223,172		10,196
Total	$	525,046	$	718	$	934,725	$	130,192	$	1,459,771	$	130,910

	December 31, 2023
	Less than 12 Months				12 Months or Longer				Total
			Gross				Gross				Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Securities AFS
U.S. treasury securities	$	49,831	$	20	$	—	$	—	$	49,831	$	20
U.S. government agency entities		18,301		108		1,313		122		19,614		230
Mortgage-backed securities		—		—		768,274		106,442		768,274		106,442
Collateralized mortgage obligations		—		—		28,044		3,194		28,044		3,194
Corporate debt securities		64,448		552		166,864		11,587		231,312		12,139
Total	$	132,580	$	680	$	964,495	$	121,345	$	1,097,075	$	122,025

As of March 31, 2024, the Company had a total of 200 securities AFS in a gross unrealized loss position with no credit impairment, consisting primarily of 156 mortgage-backed securities, and 23 Corporate debt securities, eight U.S. treasury securities, five collateralized mortgage obligations and five U.S. government agency securities. In comparison, as of December 31, 2023, the Company has a total of 192 securities AFS in a gross unrealized loss position with no credit impairment, consisting primarily of 154 mortgage-backed securities, 24 Corporate debt securities, one U.S. treasury securities, five collateralized mortgage obligations and eight U.S. government agency securities.

In March 2023, the Company recorded a $3.0 million write-off of its holdings of securities AFS from the failed Signature Bank. During the quarter ended March 31, 2024, the Company sold that security for $1.4 million.

Allowance for Credit Losses

The securities AFS that were in an unrealized loss position at March 31, 2024, were evaluated to determine whether the decline in fair value below the amortized cost basis resulted from a credit loss or other factors. For a discussion of the factors and criteria the Company uses in analyzing securities for impairment related to credit losses, see Note 1 - Summary of Significant Accounting Policies - Allowance for Credit Losses on Available for Sale Securities to the Consolidated Financial Statements in the Company’s 2023 Form 10-K.

The Company concluded the unrealized losses were primarily attributed to yield curve movement, together with widened liquidity spreads and credit spreads. The issuers have not, to the Company’s knowledge, established any cause for default on these securities. The Company expects to recover the amortized cost basis of its securities and has no present intent to sell and will not be required to sell securities AFS that have declined below their cost before their anticipated recovery. Accordingly, no allowance for credit losses was recorded as of March 31, 2024, against these securities, and there was no provision for credit losses recognized for the three months ended March 31, 2024.

Securities AFS having a carrying value of $30.6 million and $134.2 million as of March 31, 2024, and December 31, 2023, respectively, were pledged to secure public deposits and other borrowings.