Note 3 - Investment Securities (Tables)

6 Months Ended

Jun. 30, 2019

Notes Tables

Debt Securities, Available-for-sale and Held-to-maturity [Table Text Block]

	At June 30, 2019
			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
	(In thousands)
Debt securities available for sale
U.S. Treasury securities	$	44,473	$	100	$	-		$	44,573
Securities of U.S. Government sponsored entities		167,239		69		(170	)		167,138
Agency residential mortgage-backed securities (MBS)		987,024		8,236		(8,314	)		986,946
Non-agency residential MBS		109		3		-			112
Agency commercial MBS		5,635		5		(19	)		5,621
Securities of U.S. Government entities		815		-		(7	)		808
Obligations of states and political subdivisions		172,268		3,486		(100	)		175,654
Corporate securities		1,379,704		17,462		(2,119	)		1,395,047
Total debt securities available for sale		2,757,267		29,361		(10,729	)		2,775,899
Debt securities held to maturity
Agency residential MBS		402,961		824		(3,861	)		399,924
Non-agency residential MBS		2,610		96		-			2,706
Obligations of states and political subdivisions		462,418		7,947		(19	)		470,346
Total debt securities held to maturity		867,989		8,867		(3,880	)		872,976
Total	$	3,625,256	$	38,228	$	(14,609	)	$	3,648,875

	At December 31, 2018
			Gross		Gross
	Amortized		Unrealized		Unrealized			Fair
	Cost		Gains		Losses			Value
	(In thousands)
Debt securities available for sale
U.S. Treasury securities	$	139,572	$	5	$	(3	)	$	139,574
Securities of U.S. Government sponsored entities		167,228		65		(3,275	)		164,018
Agency residential MBS		883,715		595		(30,439	)		853,871
Non-agency residential MBS		113		1		-			114
Agency commercial MBS		1,869		-		(27	)		1,842
Securities of U.S. Government entities		1,128		-		(9	)		1,119
Obligations of states and political subdivisions		180,220		1,856		(2,985	)		179,091
Corporate securities		1,337,608		1,075		(23,642	)		1,315,041
Total debt securities available for sale		2,711,453		3,597		(60,380	)		2,654,670
Debt securities held to maturity
Agency residential MBS		447,332		249		(14,129	)		433,452
Non-agency residential MBS		3,387		40		-			3,427
Obligations of states and political subdivisions		533,890		3,403		(2,727	)		534,566
Total debt securities held to maturity		984,609		3,692		(16,856	)		971,445
Total	$	3,696,062	$	7,289	$	(77,236	)	$	3,626,115

Investments Classified by Contractual Maturity Date [Table Text Block]

	At June 30, 2019
	Debt Securities Available				Debt Securities Held
	for Sale				to Maturity
	Amortized		Fair		Amortized		Fair
	Cost		Value		Cost		Value
	(In thousands)
Maturity in years:
1 year or less	$	202,597	$	202,637	$	81,436	$	81,589
Over 1 to 5 years		1,329,781		1,342,419		177,675		180,218
Over 5 to 10 years		193,678		199,098		202,280		207,471
Over 10 years		38,443		39,066		1,027		1,068
Subtotal		1,764,499		1,783,220		462,418		470,346
MBS		992,768		992,679		405,571		402,630
Total	$	2,757,267	$	2,775,899	$	867,989	$	872,976

	At December 31, 2018
	Debt Securities Available				Debt Securities Held
	for Sale				to Maturity
	Amortized		Fair		Amortized		Fair
	Cost		Value		Cost		Value
	(In thousands)
Maturity in years:
1 year or less	$	262,418	$	261,976	$	86,172	$	86,148
Over 1 to 5 years		1,438,849		1,414,020		214,137		213,829
Over 5 to 10 years		85,817		85,877		232,544		233,515
Over 10 years		38,672		36,970		1,037		1,074
Subtotal		1,825,756		1,798,843		533,890		534,566
MBS		885,697		855,827		450,719		436,879
Total	$	2,711,453	$	2,654,670	$	984,609	$	971,445

Schedule of Unrealized Loss on Investments [Table Text Block]

	Debt Securities Available for Sale
	At June 30, 2019
	No. of		Less than 12 months					No. of		12 months or longer					No. of		Total
	Investment				Unrealized			Investment				Unrealized			Investment				Unrealized
	Positions		Fair Value		Losses			Positions		Fair Value		Losses			Positions		Fair Value		Losses
	($ in thousands)
Securities of U.S. Government sponsored entities		-	$	-	$	-			7	$	77,714	$	(170	)		7	$	77,714	$	(170	)
Agency residential MBS		-		-		-			54		533,982		(8,314	)		54		533,982		(8,314	)
Agency commercial MBS		-		-		-			1		1,833		(19	)		1		1,833		(19	)
Securities of U.S. Government entities		-		-		-			2		808		(7	)		2		808		(7	)
Obligations of states and political subdivisions		2		1,054		-			25		10,643		(100	)		27		11,697		(100	)
Corporate securities		2		10,692		(67	)		32		275,533		(2,052	)		34		286,225		(2,119	)
Total		4	$	11,746	$	(67	)		121	$	900,513	$	(10,662	)		125	$	912,259	$	(10,729	)

	Debt Securities Held to Maturity
	At June 30, 2019
	No. of		Less than 12 months				No. of		12 months or longer					No. of		Total
	Investment				Unrecognized		Investment				Unrecognized			Investment				Unrecognized
	Positions		Fair Value		Losses		Positions		Fair Value		Losses			Positions		Fair Value		Losses
	($ in thousands)
Agency residential MBS		1	$	55	$	-		63	$	350,418	$	(3,861	)		64	$	350,473	$	(3,861	)
Obligations of states and political subdivisions		-		-		-		13		10,516		(19	)		13		10,516		(19	)
Total		1	$	55	$	-		76	$	360,934	$	(3,880	)		77	$	360,989	$	(3,880	)

	Debt Securities Available for Sale
	At December 31, 2018
	No. of		Less than 12 months					No. of		12 months or longer					No. of		Total
	Investment				Unrealized			Investment				Unrealized			Investment				Unrealized
	Positions		Fair Value		Losses			Positions		Fair Value		Losses			Positions		Fair Value		Losses
	($ in thousands)
U.S. Treasury securities		2	$	54,805	$	(3	)		-	$	-	$	-			2	$	54,805	$	(3	)
Securities of U.S. Government sponsored entities		1		990		(5	)		9		117,963		(3,270	)		10		118,953		(3,275	)
Agency residential MBS		8		107,497		(507	)		58		640,210		(29,932	)		66		747,707		(30,439	)
Agency commercial MBS		1		1,842		(27	)		-		-		-			1		1,842		(27	)
Securities of U.S. Government entities		-		-		-			2		1,119		(9	)		2		1,119		(9	)
Obligations of states and political subdivisions		32		26,452		(166	)		71		67,121		(2,819	)		103		93,573		(2,985	)
Corporate securities		38		308,157		(3,403	)		79		722,740		(20,239	)		117		1,030,897		(23,642	)
Total		82	$	499,743	$	(4,111	)		219	$	1,549,153	$	(56,269	)		301	$	2,048,896	$	(60,380	)

	Debt Securities Held to Maturity
	At December 31, 2018
	No. of		Less than 12 months					No. of		12 months or longer					No. of		Total
	Investment				Unrecognized			Investment				Unrecognized			Investment				Unrecognized
	Positions		Fair Value		Losses			Positions		Fair Value		Losses			Positions		Fair Value		Losses
	($ in thousands)
Agency residential MBS		16	$	8,495	$	(34	)		78	$	412,574	$	(14,095	)		94	$	421,069	$	(14,129	)
Non-agency residential MBS		1		26		-			-		-		-			1		26		-
Obligations of states and political subdivisions		97		83,633		(271	)		142		151,546		(2,456	)		239		235,179		(2,727	)
Total		114	$	92,154	$	(305	)		220	$	564,120	$	(16,551	)		334	$	656,274	$	(16,856	)

Interest Income from Investments [Table Text Block]

	For the Three Months				For the Six Months
	Ended June 30,
	2019		2018		2019		2018
	(In thousands)
Taxable	$	18,773	$	15,598	$	37,406	$	30,547
Tax-exempt from regular federal income tax		4,073		5,027		8,388		9,888
Total interest income from investment securities	$	22,846	$	20,625	$	45,794	$	40,435