Investment Securities Held to Maturity

Investment securities held to maturity at December 31, 2017 and 2016 are summarized as follows (in thousands):



	2017
	Amortized cost		Gross unrealized gains	Gross unrealized losses		Fair value
Agency obligations	$	4,308	—	(87	)	4,221
Mortgage-backed securities	382		14	—		396
State and municipal obligations	462,942		9,280	(1,738	)	470,484
Corporate obligations	10,020		1	(83	)	9,938
	$	477,652	9,295	(1,908	)	485,039



	2016
	Amortized cost		Gross unrealized gains	Gross unrealized losses		Fair value
Agency obligations	$	4,306	2	(83	)	4,225
Mortgage-backed securities	893		31	—		924
State and municipal obligations	473,653		6,635	(5,436	)	474,852
Corporate obligations	9,331		7	(52	)	9,286
	$	488,183	6,675	(5,571	)	489,287

The Company generally purchases securities for long-term investment purposes, and differences between carrying and fair values may fluctuate during the investment period. Investment securities held to maturity having a carrying value of $409.7 million and $384.8 million at December 31, 2017 and 2016, respectively, were pledged to secure other borrowings, securities sold under repurchase agreements and government deposits.

The amortized cost and fair value of investment securities held to maturity at December 31, 2017 by contractual maturity are shown below (in thousands). Expected maturities may differ from contractual maturities due to prepayment or early call privileges of the issuer.



	2017
	Amortized cost		Fair value
Due in one year or less	$	7,123	7,147
Due after one year through five years	67,352		67,915
Due after five years through ten years	260,937		265,279
Due after ten years	141,858		144,302
	$	477,270	484,643

Mortgage-backed securities totaling $382,000 at amortized cost and $396,000 at fair value are excluded from the table above as their expected lives are expected to be shorter than the contractual maturity date due to principal prepayments.

During 2017, the Company recognized gains of $60,000 and losses of $3,000 related to calls on securities in the held to maturity portfolio, with total proceeds from the calls totaling $32.9 million. There were no sales of securities from the held to maturity portfolio for the year ended December 31, 2017.

For the 2016 period, the Company recognized gains of $15,000 and losses of $1,000 related to calls on securities in the held to maturity portfolio, with total proceeds from the calls totaling $45.9 million. There were no sales of securities from the held to maturity portfolio for the year ended December 31, 2016.

For the 2015 period, the Company recognized gains of $8,000 and no losses related to calls on certain securities in the held to maturity portfolio, with total proceeds from the calls totaling $27.0 million. There were no sales of securities from the held to maturity portfolio for the year ended December 31, 2015.

The following table represents the Company’s disclosure on investment securities held to maturity with temporary impairment (in thousands):



	December 31, 2017 Unrealized Losses
	Less than 12 months				12 months or longer			Total
	Fair value		Gross unrealized losses		Fair value	Gross unrealized losses		Fair value	Gross unrealized losses
Agency obligations	$	3,821	(87	)	—	—		3,821	(87	)
State and municipal obligations	37,317		(295	)	49,488	(1,443	)	86,805	(1,738	)
Corporate obligations	9,662		(83	)	—			9,662	(83	)
	$	50,800	(465	)	49,488	(1,443	)	100,288	(1,908	)



	December 31, 2016 Unrealized Losses
	Less than 12 months				12 months or longer			Total
	Fair value		Gross unrealized losses		Fair value	Gross unrealized losses		Fair value	Gross unrealized losses
Agency obligations	$	3,525	(83	)	—	—		3,525	(83	)
State and municipal obligations	172,152		(5,132	)	6,617	(304	)	178,769	(5,436	)
Corporate obligations	4,697		(52	)	—			4,697	(52	)
	$	180,374	(5,267	)	6,617	(304	)	186,991	(5,571	)

The Company estimates the loss projections for each non-agency mortgage-backed security by stressing the individual loans collateralizing the security and applying a range of expected default rates, loss severities, and prepayment speeds in conjunction with the underlying credit enhancement for each security. Based on specific assumptions about collateral and vintage, a range of possible cash flows was identified to determine whether other-than-temporary impairment existed during the year ended December 31, 2017. Based on its detailed review of the securities available for sale portfolio, the Company believes that as of December 31, 2017, securities with unrealized loss positions shown above do not represent impairments that are other-than-temporary. The Company does not have the intent to sell securities in a temporary loss position at December 31, 2017, nor is it more likely than not that the Company will be required to sell the securities before the anticipated recovery.

The number of securities in an unrealized loss position as of December 31, 2017 totaled 184, compared with 332 at December 31, 2016. All temporarily impaired investment securities were investment grade at December 31, 2017.