Investment Securities (Tables)

6 Months Ended

Jun. 30, 2018

Investments, Debt and Equity Securities [Abstract]

Schedule Of Investment Securities

Investment securities at June 30, 2018, were as follows:

Debt Securities Available-for-Sale (In thousands)	Amortized Cost		Gross Unrealized Holding  Gains		Gross Unrealized Holding  Losses		Estimated  Fair Value
U.S. Government sponsored entities' asset-backed securities	1,127,511		476		36,309		1,091,678
Total	$	1,127,511	$	476	$	36,309	$	1,091,678

Debt Securities Held-to-Maturity (In thousands)	Amortized Cost		Gross Unrecognized Holding  Gains		Gross Unrecognized Holding  Losses		Estimated Fair Value
U.S. Government sponsored entities' asset-backed securities	$	47,192	$	95	$	1,236	$	46,051
Obligations of states and political subdivisions	304,239		2,225		$	4,323	302,141
Total	$	351,431	$	2,320	$	5,559	$	348,192

Investment securities at December 31, 2017, were as follows:

Debt Securities Available-for-Sale (In thousands)	Amortized Cost		Gross Unrealized Holding  Gains		Gross Unrealized Holding  Losses		Estimated  Fair Value
Obligations of U.S. Treasury and other U.S. Government sponsored entities	$	245,000	$	—	$	2,280	$	242,720
U.S. Government sponsored entities' asset-backed securities	852,645		4,645		8,129		849,161
Total	$	1,097,645	$	4,645	$	10,409	$	1,091,881

Debt Securities Held-to-Maturity (In thousands)	Amortized Cost		Gross Unrecognized Holding  Gains		Gross Unrecognized Holding  Losses		Estimated Fair Value
Obligations of states and political subdivisions	$	300,412	$	6,575	$	713	$	306,274
U.S. Government sponsored entities' asset-backed securities	56,785		758		38		57,505
Total	$	357,197	$	7,333	$	751	$	363,779

Schedule Of Unrealized Loss On Securities

Investment securities with unrealized/unrecognized losses at June 30, 2018, were as follows:

	Unrealized/unrecognized loss position for less than 12 months				Unrealized/unrecognized loss position for 12 months or longer				Total
(In thousands)	Fair value		Unrealized/unrecognized losses		Fair value		Unrealized/unrecognized losses		Fair value		Unrealized/unrecognized losses
Debt Securities Available-for-Sale
U.S. Government sponsored entities' asset-backed securities	775,132		19,613		$	279,486	16,696		$	1,054,618	36,309
Total	$	775,132	$	19,613	$	279,486	$	16,696	$	1,054,618	$	36,309
Debt Securities Held-to-Maturity
U.S. Government sponsored entities' asset-backed securities	$	40,016	$	1,236	$	—	$	—	$	40,016	$	1,236
Obligations of states and political subdivisions	129,738		$	2,237	58,541		2,086		$	188,279	4,323
Total	$	169,754	$	3,473	$	58,541	$	2,086	$	228,295	$	5,559

Investment securities with unrealized/unrecognized losses at December 31, 2017, were as follows:

	Unrealized/unrecognized loss position for less than 12 months				Unrealized/unrecognized loss position for 12 months or longer				Total
(In thousands)	Fair value		Unrealized/unrecognized losses		Fair value		Unrealized/unrecognized losses		Fair value		Unrealized/unrecognized losses
Debt Securities Available-for-Sale
Obligations of U.S. Treasury and other U.S. Government sponsored entities	$	24,931	$	70	$	217,789	$	2,210	$	242,720	$	2,280
U.S. Government sponsored entities' asset-backed securities	236,924		2,786		318,797		5,343		555,721		8,129
Total	$	261,855	$	2,856	$	536,586	$	7,553	$	798,441	$	10,409
Debt Securities Held-to-Maturity
Obligations of states and political subdivisions	$	26,644	$	194	$	45,498	$	519	$	72,142	$	713
U.S. Government sponsored entities' asset-backed securities	7,331		38		—		—		7,331		38
Total	$	33,975	$	232	$	45,498	$	519	$	79,473	$	751

Amortized Cost And Estimated Fair Value Of Investments In Debt Securities By Contractual Maturity

The amortized cost and estimated fair value of investments in debt securities at June 30, 2018, are shown in the following table by contractual maturity, except for asset-backed securities, which are shown as a single total, due to the unpredictability of the timing of principal repayments. 

Securities Available-for-Sale (In thousands)	Amortized cost		Fair value		Tax equivalent yield
U.S. Government sponsored entities' asset-backed securities	$	1,127,511	$	1,091,678	2.35	%

Securities Held-to-Maturity (In thousands)	Amortized cost		Fair value		Tax equivalent yield (1)
Obligations of state and political subdivisions:
Due five through ten years	$	2,438	$	2,395	2.97	%
Due over ten years	$	301,801	$	299,746	3.68	%
Total (1)	$	304,239	$	302,141	3.67	%
U.S. Government sponsored entities' asset-backed securities	$	47,192	$	46,051	2.83	%