Investment Securities (Tables)

3 Months Ended

Mar. 31, 2016

Investments, Debt and Equity Securities [Abstract]

Available-for-sale Securities

The following is a summary of the amortized cost and fair value of investment securities available-for-sale and investment securities held-to-maturity at March 31, 2016, December 31, 2015 and March 31, 2015:

	Investment Securities Available-for-Sale
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
	(In thousands)
March 31, 2016
U.S. Treasury securities	$	5,777	$	20	$	—	$	5,797
Government sponsored agencies	177,537		591		491		177,637
State and political subdivisions	14,707		356		2		15,061
Residential mortgage-backed securities	178,498		899		248		179,149
Collateralized mortgage obligations	118,501		338		441		118,398
Corporate bonds	14,832		—		124		14,708
Preferred stock and trust preferred securities	2,888		377		—		3,265
Total	$	512,740	$	2,581	$	1,306	$	514,015
December 31, 2015
U.S. Treasury securities	$	5,773	$	—	$	8	$	5,765
Government sponsored agencies	195,711		78		800		194,989
State and political subdivisions	14,731		395		6		15,120
Residential mortgage-backed securities	189,452		538		2,222		187,768
Collateralized mortgage obligations	133,256		111		1,137		132,230
Corporate bonds	14,825		2		200		14,627
Preferred stock and trust preferred securities	2,888		344		—		3,232
Total	$	556,636	$	1,468	$	4,373	$	553,731
March 31, 2015
U.S. Treasury securities	$	8,271	$	31	$	—	$	8,302
Government sponsored agencies	249,642		889		101		250,430
State and political subdivisions	31,701		624		3		32,322
Residential mortgage-backed securities	218,299		1,358		56		219,601
Collateralized mortgage obligations	133,713		305		718		133,300
Corporate bonds	34,925		136		64		34,997
Preferred stock	1,389		303		—		1,692
Total	$	677,940	$	3,646	$	942	$	680,644

Held-to-maturity Securities

	Investment Securities Held-to-Maturity
	Amortized Cost		Unrealized Gains		Unrealized Losses		Fair Value
	(In thousands)
March 31, 2016
State and political subdivisions	$	517,800	$	9,493	$	1,985	$	525,308
Trust preferred securities	500		—		215		285
Total	$	518,300	$	9,493	$	2,200	$	525,593
December 31, 2015
State and political subdivisions	$	509,471	$	7,446	$	4,512	$	512,405
Trust preferred securities	500		—		200		300
Total	$	509,971	$	7,446	$	4,712	$	512,705
March 31, 2015
State and political subdivisions	$	370,950	$	6,852	$	4,926	$	372,876
Trust preferred securities	10,500		—		3,200		7,300
Total	$	381,450	$	6,852	$	8,126	$	380,176

Amortized cost and fair value of debt securities by contractual maturity

The following is a summary of the amortized cost and fair value of investment securities at March 31, 2016, by maturity, for both available-for-sale and held-to-maturity investment securities. The maturities of residential mortgage-backed securities and collateralized mortgage obligations are based on scheduled principal payments. The maturities of all other debt securities are based on final contractual maturity.

	March 31, 2016
	Amortized Cost		Fair Value
	(In thousands)
Investment Securities Available-for-Sale:
Due in one year or less	$	167,082	$	167,114
Due after one year through five years	293,731		294,443
Due after five years through ten years	45,820		45,935
Due after ten years	4,719		4,757
Preferred stock	1,388		1,766
Total	$	512,740	$	514,015
Investment Securities Held-to-Maturity:
Due in one year or less	$	57,074	$	57,148
Due after one year through five years	239,496		241,445
Due after five years through ten years	142,968		145,988
Due after ten years	78,762		81,012
Total	$	518,300	$	525,593

Summary of continuous unrealized loss position of securities

The following schedule summarizes information for both available-for-sale and held-to-maturity investment securities with gross unrealized losses at March 31, 2016, December 31, 2015 and March 31, 2015, aggregated by category and length of time that individual securities have been in a continuous unrealized loss position.

	Less Than 12 Months				12 Months or More				Total
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
	(In thousands)
March 31, 2016
Government sponsored agencies	$	2,501	$	1	$	20,275	$	490	$	22,776	$	491
State and political subdivisions	83,997		1,067		96,143		920		180,140		1,987
Residential mortgage-backed securities	54,163		63		63,869		185		118,032		248
Collateralized mortgage obligations	29,973		34		35,489		407		65,462		441
Corporate bonds	4,666		73		4,950		51		9,616		124
Trust preferred securities	—		—		285		215		285		215
Total	$	175,300	$	1,238	$	221,011	$	2,268	$	396,311	$	3,506
December 31, 2015
U.S. Treasury securities	$	5,765	$	8	$	—	$	—	$	5,765	$	8
Government sponsored agencies	114,640		292		21,681		508		136,321		800
State and political subdivisions	195,285		2,891		68,361		1,627		263,646		4,518
Residential mortgage-backed securities	169,226		2,146		3,435		76		172,661		2,222
Collateralized mortgage obligations	60,459		408		39,382		729		99,841		1,137
Corporate bonds	9,532		200		—		—		9,532		200
Trust preferred securities	—		—		300		200		300		200
Total	$	554,907	$	5,945	$	133,159	$	3,140	$	688,066	$	9,085
March 31, 2015
Government sponsored agencies	$	27,889	$	64	$	18,896	$	37	$	46,785	$	101
State and political subdivisions	156,010		1,989		49,839		2,940		205,849		4,929
Residential mortgage-backed securities	82,303		28		3,847		28		86,150		56
Collateralized mortgage obligations	22,694		22		41,061		696		63,755		718
Corporate bonds	4,989		11		14,946		53		19,935		64
Trust preferred securities	—		—		7,300		3,200		7,300		3,200
Total	$	293,885	$	2,114	$	135,889	$	6,954	$	429,774	$	9,068