Securities (Tables)

3 Months Ended

Mar. 31, 2017

Securities [Abstract]

Summary of Amortized Cost and Fair Value of Available-for-sale and Held-to-maturity Securities

The amortized cost and fair value of securities available-for-sale and held-to-maturity at March 31, 2017 and December 31, 2016 are summarized as follows (in thousands):

	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
March 31, 2017:
Securities available-for-sale:
U.S. Treasury securities	$	250	$	-	$	-	$	250
U.S. government agency securities		19,213		1		275		18,939
Mortgage-backed agency securities		1,240,671		4,205		17,899		1,226,977
State and municipal securities		247,210		4,611		2,824		248,997
Asset-backed securities		71,942		108		729		71,321
Corporate notes and other		13,245		152		105		13,292
	$	1,592,531	$	9,077	$	21,832	$	1,579,776
Securities held-to-maturity:
State and municipal securities	$	24,998	$	124	$	86	$	25,036
	$	24,998	$	124	$	86	$	25,036

December 31, 2016:
Securities available-for-sale:
U.S. Treasury securities	$	250	$	-	$	-	$	250
U.S. government agency securities		22,306		-		537		21,769
Mortgage-backed agency securities		988,008		4,304		15,686		976,626
State and municipal securities		211,581		4,103		2,964		212,720
Asset-backed securities		79,318		111		849		78,580
Corporate notes and other		8,608		39		46		8,601
	$	1,310,071	$	8,557		20,082	$	1,298,546
Securities held-to-maturity:
State and municipal securities	$	25,251	$	87	$	105	$	25,233
	$	25,251	$	87	$	105	$	25,233

Amortized Cost and Fair Value of Debt Securities by Contractual Maturity

The amortized cost and fair value of debt securities as of March 31, 2017 by contractual maturity are shown below. Actual maturities may differ from contractual maturities of mortgage- and asset-backed securities since the mortgages and assets underlying the securities may be called or prepaid with or without penalty. Therefore, these securities are not included in the maturity categories in the following summary (in thousands):

	Available-for-sale				Held-to-maturity
March 31, 2017:	Amortized Cost		Fair Value		Amortized Cost		Fair Value
Due in one year or less	$	2,519	$	2,536	$	445	$	445
Due in one year to five years		45,041		46,143		8,262		8,285
Due in five years to ten years		128,637		130,524		10,817		10,897
Due after ten years		103,721		102,275		5,474		5,409
Mortgage-backed securities		1,240,671		1,226,977		-		-
Asset-backed securities		71,942		71,321		-		-
	$	1,592,531	$	1,579,776	$	24,998	$	25,036

Classification of Investments According to Term of Unrealized Losses of Less than Twelve Months or Twelve Months or Longer

At March 31, 2017 and December 31, 2016, the following investments had unrealized losses. The table below classifies these investments according to the term of the unrealized losses of less than twelve months or twelve months or longer (in thousands):

	Investments with an Unrealized Loss of less than 12 months				Investments with an Unrealized Loss of 12 months or longer				Total Investments with an Unrealized Loss
	Fair Value		Unrealized Losses		Fair Value		Unrealized Losses		Fair Value		Unrealized Losses
At March 31, 2017
U.S. Treasury securities	$	-	$	-	$	-	$	-	$	-	$	-
U.S. government agency securities		749		1		12,995		274		13,744		275
Mortgage-backed securities		1,009,381		17,214		53,060		685		1,062,441		17,899
State and municipal securities		101,430		2,909		310		1		101,740		2,910
Asset-backed securities		11,008		24		25,928		705		36,936		729
Corporate notes		4,542		105		-		-		4,542		105
Total temporarily-impaired securities	$	1,127,110	$	20,253	$	92,293	$	1,665	$	1,219,403	$	21,918
At December 31, 2016
U.S. Treasury securities	$	-	$	-	$	-	$	-	$	-	$	-
U.S. government agency securities		-		-		20,820		537		20,820		537
Mortgage-backed securities		801,213		15,073		43,148		613		844,361		15,686
State and municipal securities		87,277		3,068		312		1		87,589		3,069
Asset-backed securities		14,510		32		34,097		817		48,607		849
Corporate notes		4,810		46		-		-		4,810		46
Total temporarily-impaired securities	$	907,810	$	18,219	$	98,377	$	1,968	$	1,006,187	$	20,187