Securities (Tables)

9 Months Ended

Sep. 30, 2020

Investments Debt And Equity Securities [Abstract]

Summary of Amortized Cost and Fair Values of Securities Available-for-sale, and Held to Maturity

The following tables summarize the amortized cost and fair values of securities available-for-sale and securities held-to-maturity as of the dates shown and the corresponding amounts of gross unrealized gains and losses:

September 30, 2020	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available-for-sale
U.S. Treasury Notes	$	25,456	$	495	$	—		$	25,951
U.S. Government agencies		104,253		814		(357	)		104,710
Obligations of states, municipalities, and political subdivisions		103,895		4,417		—			108,312
Residential mortgage-backed securities
Agency		807,798		16,594		(355	)		824,037
Non-agency		62,775		1,321		—			64,096
Commercial mortgage-backed securities
Agency		256,830		7,415		(513	)		263,732
Non-agency		11,215		428		—			11,643
Corporate securities		56,059		1,364		(215	)		57,208
Asset-backed securities		50,354		89		(921	)		49,522
Total	$	1,478,635	$	32,937	$	(2,361	)	$	1,509,211

September 30, 2020	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Held-to-maturity
Obligations of states, municipalities, and political subdivisions	$	4,400	$	189	$	—	$	4,589
Total	$	4,400	$	189	$	—	$	4,589

December 31, 2019	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
Available-for-sale
U.S. Treasury Notes	$	41,403	$	427	$	—		$	41,830
U.S. Government agencies		165,162		542		(754	)		164,950
Obligations of states, municipalities, and political subdivisions		92,806		2,075		(49	)		94,832
Residential mortgage-backed securities
Agency		490,427		2,163		(2,354	)		490,236
Non-agency		109,501		593		(272	)		109,822
Commercial mortgage-backed securities
Agency		159,650		1,092		(1,041	)		159,701
Non-agency		31,144		130		—			31,274
Corporate securities		48,796		571		(37	)		49,330
Asset-backed securities		44,515		—		(198	)		44,317
Total	$	1,183,404	$	7,593	$	(4,705	)	$	1,186,292

December 31, 2019	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Held-to-maturity
Obligations of states, municipalities, and political    subdivisions	$	4,412	$	86	$	—	$	4,498
Total	$	4,412	$	86	$	—	$	4,498

Summary of Gross Unrealized Losses and Fair Values, Aggregated by Investment Category and Length of Individual Securities Continuous Unrealized Loss Position Available-for-sale and Held to Maturity

Gross unrealized losses and fair values, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of September 30, 2020 and December 31, 2019, are summarized as follows:

			Less than 12 Months					12 Months or Longer					Total
September 30, 2020	# of Securities		Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Available-for-sale
U.S. Government agencies		7	$	50,779	$	(357	)	$	—	$	—		$	50,779	$	(357	)
Obligations of states, municipalities and political subdivisions		1		126		—			—		—			126		—
Residential mortgage-backed securities
Agency		11		116,877		(349	)		503		(6	)		117,380		(355	)
Commercial mortgage-backed securities
Agency		7		59,474		(513	)		—		—			59,474		(513	)
Corporate securities		7		12,304		(215	)		—		—			12,304		(215	)
Asset-backed securities		8		19,239		(301	)		19,200		(620	)		38,439		(921	)
Total		41	$	258,799	$	(1,735	)	$	19,703	$	(626	)	$	278,502	$	(2,361	)

			Less than 12 Months					12 Months or Longer					Total
December 31, 2019	# of Securities		Fair Value		Unrealized Losses			Fair Value		Unrealized Losses			Fair Value		Unrealized Losses
Available-for-sale
U.S. Government agencies		8	$	49,318	$	(662	)	$	20,283	$	(92	)	$	69,601	$	(754	)
Obligations of states, municipalities and    political subdivisions		7		13,309		(45	)		1,419		(4	)		14,728		(49	)
Residential mortgage-backed securities
Agency		50		132,703		(666	)		193,363		(1,688	)		326,066		(2,354	)
Non-agency		9		36,902		(206	)		10,126		(66	)		47,028		(272	)
Commercial mortgage-backed securities
Agency		13		67,649		(563	)		32,678		(478	)		100,327		(1,041	)
Corporate securities		4		6,103		(37	)		—		—			6,103		(37	)
Asset-backed securities		8		37,738		(198	)		—		—			37,738		(198	)
Total		99	$	343,722	$	(2,377	)	$	257,869	$	(2,328	)	$	601,591	$	(4,705	)

Summary of Proceeds From Sales of Securities Available-for-sale and Associated Gains and Losses

The proceeds from all sales of securities available-for-sale, and the associated gains and losses, for the three and nine months ended September 30, 2020 and 2019 are listed below:

	For the Three Months Ended				For the Nine Months Ended
	September 30,				September 30,
	2020		2019		2020		2019
Proceeds	$	35,092	$	32,509	$	80,509	$	92,103
Gross gains		1,037		225		2,494		1,274
Gross losses		—		47		82		123

Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity

At September 30, 2020, the amortized cost and fair value of debt securities are shown by contractual maturity. Expected maturities may differ from contractual maturities if borrowers have the right to call or prepay obligations with or without call or prepayment penalties. Securities not due at a single maturity date are shown separately. 

	Amortized Cost		Fair Value
Available-for-sale
Due in one year or less	$	26,009	$	26,278
Due from one to five years		46,331		48,014
Due from five to ten years		163,361		166,150
Due after ten years		104,316		105,261
Mortgage-backed securities		1,138,618		1,163,508
Total	$	1,478,635	$	1,509,211
Held-to-maturity
Due in one year or less	$	502	$	505
Due from one to five years		3,898		4,084
Total	$	4,400	$	4,589