Note 4 - Investment Securities (Tables)

9 Months Ended

Sep. 30, 2026

Notes Tables

Schedule of Available-for-Sale Securities Reconciliation [Table Text Block]

	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

Investments Classified by Contractual Maturity Date [Table Text Block]

	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

Unrealized Gain (Loss) on Investments [Table Text Block]

	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