Note 4 - Investment Securities

9 Months Ended

Sep. 30, 2026

Notes to Financial Statements

Investment in Debt and Equity Securities and Other Trading Assets [Text Block]

4. 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  September 30, 2026, and  December 31, 2025.

	September 30, 2026
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	($ In thousands)
Securities AFS
U.S. treasury securities	$	925,220	$	—	$	573	$	924,647
U.S. government agency entities		611		51		84		578
Mortgage-backed securities		701,414		43		66,840		634,617
Collateralized mortgage obligations		5,638		—		1,429		4,209
Corporate debt securities		25,000		5		20		24,985
Total	$	1,657,883	$	99	$	68,946	$	1,589,036

	December 31, 2025
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	($ In thousands)
Securities AFS
U.S. treasury securities	$	827,763	$	430	$	—	$	828,193
U.S. government agency entities		5,888		52		118		5,822
U.S. government sponsored entities		25,000		11		—		25,011
Mortgage-backed securities		704,213		548		75,324		629,437
Collateralized mortgage obligations		24,454		—		1,706		22,748
Corporate debt securities		148,133		101		1,222		147,012
Total	$	1,735,451	$	1,142	$	78,370	$	1,658,223

AFS securities with carrying value of $19.7 million and $22.8 million as of  September 30, 2026, and December 31, 2025, respectively, were pledged to secure public deposits and other borrowings.

As of   September 30, 2026, and  December 31, 2025, accrued interest receivables on AFS securities totaled $2.7 million and $3.0 million, respectively. These amounts are excluded from the securities' amortized cost and included in accrued interest receivable on the Consolidated Balance Sheets. For the Company’s accounting policy related to accrued interest receivable on AFS securities, 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 2025 Form 10-K.

The amortized cost and fair value of AFS securities as of  September 30, 2026, by contractual maturities, are set forth in the table 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.  

	September 30, 2026
	Securities AFS
	Amortized Cost		Fair Value
	($ In thousands)
Due in one year or less	$	935,275	$	934,634
Due after one year through five years		15,297		15,297
Due after five years through ten years		1,510		1,295
Due after ten years		705,801		637,810
Total	$	1,657,883	$	1,589,036

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  September 30, 2026, and  December 31, 2025.

	September 30, 2026
	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	$	874,647	$	573	$	—	$	—	$	874,647	$	573
U.S. government agency entities		—		—		513		84		513		84
Mortgage-backed securities		431,123		21,379		203,135		45,461		634,258		66,840
Collateralized mortgage obligations		—		—		4,209		1,429		4,209		1,429
Corporate debt securities		—		—		9,980		20		9,980		20
Total	$	1,305,770	$	21,952	$	217,837	$	46,994	$	1,523,607	$	68,946

	December 31, 2025
	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. government agency entities	$	834	$	1	$	3,585	$	117	$	4,419	$	118
Mortgage-backed securities		207		—		600,658		75,324		600,865		75,324
Collateralized mortgage obligations		—		—		22,747		1,706		22,747		1,706
Corporate debt securities		—		—		76,912		1,222		76,912		1,222
Total	$	1,041	$	1	$	703,902	$	78,369	$	704,943	$	78,370

As of  September 30, 2026, the Company had a total of 92 AFS securities in a gross unrealized loss position with no credit impairment, consisting primarily of 68 mortgage-backed securities, 18 U.S. treasury securities, four U.S. government agency securities, one corporate debt security, and one collateralized mortgage obligation. As of  December 31, 2025, the Company had a total of 159 AFS securities in a gross unrealized loss position with no credit impairment, consisting primarily of 138 mortgage-backed securities, ten U.S. government agency securities, eight corporate debt securities, and three collateralized mortgage obligations.

The AFS securities that were in an unrealized loss position at  September 30, 2026, 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 2025 Form 10-K.

During the quarter ended  September 30, 2026, the Company sold certain available-for-sale investment securities with an amortized cost basis of $89.8 million and recognized a loss of $15.1 million related to investment securities repositioning activities. For the nine months ended  September 30, 2026, the Company sold lower-yielding securities with an amortized cost of $460.3 million and recognized a realized loss of $41.3 million.

The unrealized losses on the remaining AFS securities were primarily attributable to changes in the yield curve and wider liquidity and credit spreads. The issuers have not, to the Company’s knowledge, exhibited any conditions that would indicate a risk of default. Other than the securities sold, the Company expects to recover the amortized cost basis of its AFS securities and has no intent to sell, nor is it more likely than not that it will be required to sell, securities in an unrealized loss position before recovery. Accordingly, no allowance for credit losses was recorded on AFS securities as of  September 30, 2026, and no provision for credit losses was recognized for the quarter.