Securities

The following tables present the amortized cost, gross unrealized holding gains, gross unrealized holding losses and fair value of securities by major security type and class of security:



(Dollars in thousands)
March 31, 2019	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Available for Sale Debt Securities:
Obligations of U.S. government-sponsored enterprises		$246,717		$682		($1,927	)		$245,472
Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises	727,511		4,341		(8,347		)	723,505
Obligations of states and political subdivisions	935		2		—			937
Individual name issuer trust preferred debt securities	13,311		—		(941		)	12,370
Corporate bonds	13,911		9		(1,323		)	12,597
Total available for sale debt securities		$1,002,385		$5,034		($12,538	)		$994,881
Total securities		$1,002,385		$5,034		($12,538	)		$994,881



(Dollars in thousands)
December 31, 2018	Amortized Cost		Unrealized Gains		Unrealized Losses			Fair Value
Available for Sale Debt Securities:
Obligations of U.S. government-sponsored enterprises		$246,708		$442		($4,467	)		$242,683
Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises	675,368		1,943		(16,518		)	660,793
Obligations of states and political subdivisions	935		2		—			937
Individual name issuer trust preferred debt securities	13,307		—		(1,535		)	11,772
Corporate bonds	13,402		—		(1,777		)	11,625
Total available for sale debt securities		$949,720		$2,387		($24,297	)		$927,810
Held to Maturity Debt Securities:
Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises		$10,415		$—		($99	)		$10,316
Total held to maturity debt securities		$10,415		$—		($99	)		$10,316
Total securities		$960,135		$2,387		($24,396	)		$938,126

As discussed in Note 2, on January 1, 2019, the Corporation adopted ASU 2017-12. As permitted by ASU 2017-12, qualifying debt securities classified as held to maturity with an amortized cost of $10.4 million and a fair value of $10.3 million were reclassified to available for sale upon the adoption date. An unrealized loss of $75 thousand (net of taxes) was recognized in the accumulated other comprehensive income component of shareholders’ equity at the date of adoption.

As of March 31, 2019 and December 31, 2018, debt securities with a fair value of $497.5 million and $439.7 million, respectively, were pledged as collateral for FHLB borrowings, potential borrowings with the FRB, certain public deposits and for other purposes. See Note 7 for additional disclosure on FHLB borrowings.

The schedule of maturities of available for sale debt securities is presented below. Mortgage-backed securities are included based on weighted average maturities, adjusted for anticipated prepayments. All other debt securities are included based on contractual maturities. Actual maturities may differ from amounts presented because certain issuers have the right to call or prepay obligations with or without call or prepayment penalties.



(Dollars in thousands)	Available for Sale
March 31, 2019	Amortized Cost		Fair Value
Due in one year or less		$74,364		$73,944
Due after one year to five years	345,082		343,090
Due after five years to ten years	351,603		348,484
Due after ten years	231,336		229,363
Total debt securities		$1,002,385		$994,881

Included in the above table are debt securities with an amortized cost balance of $273.4 million and a fair value of $269.8 million at March 31, 2019 that are callable at the discretion of the issuers. Final maturities of the callable securities range from 2 months to 18 years, with call features ranging from 1 month to 4 years.

Other-Than-Temporary Impairment Assessment

Management assesses whether the decline in fair value of investment securities is other-than-temporary on a regular basis. Unrealized losses on debt securities may occur from current market conditions, increases in interest rates since the time of purchase, a structural change in an investment, volatility of earnings of a specific issuer, or deterioration in credit quality of the issuer. Management evaluates impairments in value both qualitatively and quantitatively to assess whether they are other-than-temporary.

The following tables summarize temporarily impaired securities, segregated by length of time the securities have been in a continuous unrealized loss position:



(Dollars in thousands)	Less than 12 Months					12 Months or Longer						Total
March 31, 2019	#	Fair Value		Unrealized Losses		#	Fair Value		Unrealized Losses			#	Fair Value		Unrealized Losses
Obligations of U.S. government-sponsored enterprises	—		$—		$—	14		$139,573		($1,927	)	14		$139,573		($1,927	)
Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises	—	—		—		47	409,374		(8,347		)	47	409,374		(8,347		)
Individual name issuer trust preferred debt securities	—	—		—		5	12,370		(941		)	5	12,370		(941		)
Corporate bonds	—	—		—		7	11,874		(1,323		)	7	11,874		(1,323		)
Total temporarily impaired securities	—		$—		$—	73		$573,191		($12,538	)	73		$573,191		($12,538	)



(Dollars in thousands)	Less than 12 Months						12 Months or Longer						Total
December 31, 2018	#	Fair Value		Unrealized Losses			#	Fair Value		Unrealized Losses			#	Fair Value		Unrealized Losses
Obligations of U.S. government-sponsored enterprises	—		$—		$—		16		$157,032		($4,467	)	16		$157,032		($4,467	)
Mortgage-backed securities issued by U.S. government agencies and U.S. government-sponsored enterprises	10	47,060		(439		)	51	438,701		(16,178		)	61	485,761		(16,617		)
Individual name issuer trust preferred debt securities	—	—		—			5	11,772		(1,535		)	5	11,772		(1,535		)
Corporate bonds	3	1,198		(9		)	5	10,427		(1,768		)	8	11,625		(1,777		)
Total temporarily impaired securities	13		$48,258		($448	)	77		$617,932		($23,948	)	90		$666,190		($24,396	)

Further deterioration in credit quality of the underlying issuers of the securities, deterioration in the condition of the financial services industry, worsening of the current economic environment, or additional declines in real estate values, among other things, may further affect the fair value of these securities and increase the potential that certain unrealized losses be designated as other-than-temporary in future periods, and the Corporation may incur write-downs.

Obligations of U.S. Government Agency and U.S. Government-Sponsored Enterprise Securities, including Mortgage-Backed Securities

The gross unrealized losses on U.S. government agency and U.S. government-sponsored debt securities, including mortgage-backed securities, were primarily attributable to relative changes in interest rates since the time of purchase. The contractual cash flows for these securities are guaranteed by U.S. government agencies and U.S. government-sponsored enterprises. Management believes that the unrealized losses on these debt security holdings are a function of changes in investment spreads and interest rate movements and not changes in credit quality. Management expects to recover the entire amortized cost basis of these securities. Furthermore, the Corporation does not intend to sell these securities and it is not more-likely-than-not that the Corporation will be required to sell these securities before recovery of their cost basis, which may be maturity. Therefore, management does not consider these investments to be other-than-temporarily impaired at March 31, 2019.

Individual Name Issuer Trust Preferred Debt Securities

Included in debt securities in an unrealized loss position at March 31, 2019 were five trust preferred securities issued by four individual companies in the banking sector. Management believes the unrealized losses on these holdings were attributable to the general widening of spreads for this category of debt securities issued by financial services companies since the time these securities were purchased. Based on the information available through the filing date of this report, all individual name issuer trust preferred debt securities held in our portfolio continue to accrue interest and make payments as expected with no payment deferrals or defaults on the part of the issuers. As of March 31, 2019, individual name issuer trust preferred debt securities with an amortized cost of $6.1 million and unrealized losses of $446 thousand were rated below investment grade by Standard & Poors, Inc. (“S&P”). Management reviewed the collectibility of these securities taking into consideration such factors as the financial condition of the issuers, reported regulatory capital ratios of the issuers, credit ratings, including ratings in effect as of the reporting period date as well as credit rating changes between the reporting period date and the filing date of this report, and other information. We noted no additional downgrades to below investment grade between March 31, 2019 and the filing date of this report. Based on this review, management concluded that it expects to recover the entire amortized cost basis of these securities. Furthermore, the Corporation does not intend to sell these securities and it is not more-likely-than-not that the Corporation will be required to sell these securities before recovery of their cost basis, which may be maturity. Therefore, management does not consider these investments to be other-than-temporarily impaired at March 31, 2019.

Corporate Bonds

At March 31, 2019, the Corporation had seven corporate bond holdings with unrealized losses totaling $1.3 million. These investment grade corporate bonds were issued by large corporations, primarily in the financial services industry. Management believes the unrealized losses on these bonds are a function of the changes in the investment spreads and interest rate movements and not changes in the credit quality of the issuers of the debt securities. Management expects to recover the entire amortized cost basis of these securities. Furthermore, the Corporation does not intend to sell these securities and it is not more-likely-than-not that the Corporation will be required to sell these securities before recovery of their cost basis, which may be maturity. Therefore, management does not consider these investments to be other-than-temporarily impaired at March 31, 2019.