Note 7 - Investment Securities (Tables)

3 Months Ended

Mar. 31, 2019

Notes Tables

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

	March 31, 2019
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	149,231	$	20	$	11	$	149,240
U.S. government agency entities		5,694		3		166		5,531
U.S. government sponsored entities		400,000		—		6,726		393,274
Mortgage-backed securities		701,761		2,391		8,191		695,961
Collateralized mortgage obligations		905		—		24		881
Corporate debt securities		64,988		211		233		64,966
Total	$	1,322,579	$	2,625	$	15,351	$	1,309,853

	December 31, 2018
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	124,801	$	—	$	51	$	124,750
U.S. government agency entities		6,066		—		195		5,871
U.S. government sponsored entities		400,000		—		11,637		388,363
Mortgage-backed securities		670,874		960		15,089		656,745
Collateralized mortgage obligations		1,005		—		28		977
Corporate debt securities		64,985		818		—		65,803
Total	$	1,267,731	$	1,778	$	27,000	$	1,242,509

Investments Classified by Contractual Maturity Date [Table Text Block]

	Securities Available-For-Sale
	Amortized Cost		Fair Value
	(In thousands)
Due in one year or less	$	149,234	$	149,243
Due after one year through five years		465,744		459,017
Due after five years through ten years		5,820		5,662
Due after ten years		701,781		695,931
Total	$	1,322,579	$	1,309,853

Schedule of Unrealized Loss on Investments [Table Text Block]

	March 31, 2019
	Less than 12 Months				12 Months or Longer				Total
			Gross								Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	99,779	$	11	$	—	$	—	$	99,779	$	11
U.S. government agency entities		—		—		4,577		166		4,577		166
U.S. government sponsored entities		—		—		393,274		6,726		393,274		6,726
Mortgage-backed securities		3,437		18		511,556		8,173		514,993		8,191
Collateralized mortgage obligations		—		—		881		24		881		24
Corporate debt securities		39,767		233		—		—		39,767		233
Total	$	142,983	$	262	$	910,288	$	15,089	$	1,053,271	$	15,351

	December 31, 2018
	Less than 12 Months				12 Months or Longer				Total
			Gross								Gross
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	124,751	$	51	$	—	$	—	$	124,751	$	51
U.S. government agency entities		3,388		77		2,483		118		5,871		195
U.S. government sponsored entities		—		—		388,362		11,637		388,362		11,637
Mortgage-backed securities		48,528		502		507,701		14,587		556,229		15,089
Collateralized mortgage obligations		—		—		977		28		977		28
Total	$	176,667	$	630	$	899,523	$	26,370	$	1,076,190	$	27,000