Note 6 - Investment Securities (Tables)

6 Months Ended

Jun. 30, 2017

Notes Tables

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

	June 30, 2017
			Gross		Gross
	Amortized		Unrealized		Unrealized
	Cost		Gains		Losses		Fair Value
	(In thousands)
Securities Available-for-Sale
U.S. treasury securities	$	569,569	$	-	$	524	$	569,045
U.S. government sponsored entities		400,000		-		5,369		394,631
Mortgage-backed securities		309,166		221		2,480		306,907
Corporate debt securities		74,970		549		109		75,410
Mutual funds		6,500		-		235		6,265
Preferred stock of government sponsored entities		2,811		2,413		-		5,224
Other equity securities		3,608		7,261		-		10,869
Total	$	1,366,624	$	10,444	$	8,717	$	1,368,351

	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	$	520,258	$	520,058
Due after one year through five years		526,194		521,010
Due after five years through ten years		95		102
Due after ten years (1)		320,077		327,181
Total	$	1,366,624	$	1,368,351

Schedule of Unrealized Loss on Investments [Table Text Block]

	June 30, 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	$	569,044	$	524	$	-	$	-	$	569,044	$	524
U.S. government sponsored entities		394,631		5,369		-		-		394,631		5,369
Mortgage-backed securities		301,997		2,477		56		3		302,053		2,480
Corporate debt securities		-		-		29,891		109		29,891		109
Mutual funds		-		-		6,265		235		6,265		235
Total	$	1,265,672	$	8,370	$	36,212	$	347	$	1,301,884	$	8,717

	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