Note 6 - Investment Securities (Tables)

3 Months Ended

Mar. 31, 2017

Notes Tables

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

	March 31, 2017
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	419,881	$	-	$	411	$	419,470
U.S. government sponsored entities		400,000		-		8,014		391,986
Mortgage-backed securities		323,017		268		3,124		320,161
Corporate debt securities		74,968		378		335		75,011
Mutual funds		6,500		-		270		6,230
Preferred stock of government sponsored entities		2,811		3,167		-		5,978
Other equity securities		3,608		5,285		-		8,893
Total	$	1,230,785	$	9,098	$	12,154	$	1,227,729

	December 31, 2016
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	489,839	$	35	$	857	$	489,017
U.S. government sponsored entities		400,000		-		9,669		390,331
Mortgage-backed securities		339,241		309		3,290		336,260
Collateralized mortgage obligations		48		-		20		28
Corporate debt securities		74,965		247		862		74,350
Mutual funds		6,500		-		270		6,230
Preferred stock of government sponsored entities		2,811		4,497		-		7,308
Other equity securities		3,608		7,213		-		10,821
Total	$	1,317,012	$	12,301	$	14,968	$	1,314,345

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	$	370,028	$	369,892
Due after one year through five years		527,354		519,205
Due after five years through ten years		103		111
Due after ten years (1)		333,300		338,521
Total	$	1,230,785	$	1,227,729

Schedule of Unrealized Loss on Investments [Table Text Block]

	March 31, 2017
	Temporarily impaired securities
	Less than 12 months				12 months or longer				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	419,470	$	411	$	-	$	-	$	419,470	$	411
U.S. government sponsored entities		391,986		8,014		-		-		391,986		8,014
Mortgage-backed securities		314,395		3,120		58		3		314,453		3,123
Corporate debt securities		4,993		7		29,671		329		34,664		336
Mutual funds		-		-		6,230		270		6,230		270
Total	$	1,130,844	$	11,552	$	35,959	$	602	$	1,166,803	$	12,154

	December 31, 2016
	Temporarily impaired securities
	Less than 12 months				12 months or longer				Total
	Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
	Value		Losses		Value		Losses		Value		Losses
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	299,088	$	857	$	-	$	-	$	299,088	$	857
U.S. government sponsored entities		390,331		9,669		-		-		390,331		9,669
Mortgage-backed securities		328,236		3,288		62		2		328,298		3,290
Collateralized mortgage obligations		-		-		28		20		28		20
Corporate debt securities		-		-		29,138		862		29,138		862
Mutual funds		-		-		6,230		270		6,230		270
Total	$	1,017,655	$	13,814	$	35,458	$	1,154	$	1,053,113	$	14,968