| Investment Securities |
Investment Securities The following tables present the amortized costs, unrealized gains, unrealized losses and approximate fair values of investment securities at June 30, 2017 and December 31, 2016:
| | | | | | | | | | | | | | | | | (in thousands) | June 30, 2017 | | Amortized | | Unrealized | | Unrealized | | Fair | | Cost | | Gains | | Losses | | Value | AVAILABLE FOR SALE: | |
| | |
| | |
| | |
| Obligations of states and political subdivisions | $ | 292,528 |
| | $ | 7,091 |
| | $ | (1,059 | ) | | $ | 298,560 |
| Residential mortgage-backed securities and collateralized mortgage obligations | 2,854,484 |
| | 5,177 |
| | (27,636 | ) | | 2,832,025 |
| Investments in mutual funds and other equity securities | 1,959 |
| | 22 |
| | — |
| | 1,981 |
| | $ | 3,148,971 |
| | $ | 12,290 |
| | $ | (28,695 | ) | | $ | 3,132,566 |
| HELD TO MATURITY: | | | | | | | | Residential mortgage-backed securities and collateralized mortgage obligations | $ | 4,017 |
| | $ | 1,054 |
| | $ | — |
| | $ | 5,071 |
| | $ | 4,017 |
| | $ | 1,054 |
| | $ | — |
| | $ | 5,071 |
|
| | | | | | | | | | | | | | | | | (in thousands) | December 31, 2016 | | Amortized | | Unrealized | | Unrealized | | Fair | | Cost | | Gains | | Losses | | Value | AVAILABLE FOR SALE: | | | | | | | | Obligations of states and political subdivisions | $ | 305,708 |
| | $ | 5,526 |
| | $ | (3,537 | ) | | $ | 307,697 |
| Residential mortgage-backed securities and collateralized mortgage obligations | 2,428,387 |
| | 3,664 |
| | (40,498 | ) | | 2,391,553 |
| Investments in mutual funds and other equity securities | 1,959 |
| | 11 |
| | — |
| | 1,970 |
| | $ | 2,736,054 |
| | $ | 9,201 |
| | $ | (44,035 | ) | | $ | 2,701,220 |
| HELD TO MATURITY: | | | | | | | | Residential mortgage-backed securities and collateralized mortgage obligations | $ | 4,216 |
| | $ | 1,001 |
| | $ | — |
| | $ | 5,217 |
| | $ | 4,216 |
| | $ | 1,001 |
| | $ | — |
| | $ | 5,217 |
|
Investment securities that were in an unrealized loss position as of June 30, 2017 and December 31, 2016 are presented in the following tables, based on the length of time individual securities have been in an unrealized loss position. | | | | | | | | | | | | | | | | | | | | | | | | | June 30, 2017 | | | | | | | | | | | | (in thousands) | Less than 12 Months | | 12 Months or Longer | | Total | | Fair | | Unrealized | | Fair | | Unrealized | | Fair | | Unrealized | | Value | | Losses | | Value | | Losses | | Value | | Losses | AVAILABLE FOR SALE: | | | | | | | | | | | | Obligations of states and political subdivisions | $ | 32,681 |
| | $ | 816 |
| | $ | 6,187 |
| | $ | 243 |
| | $ | 38,868 |
| | $ | 1,059 |
| Residential mortgage-backed securities and collateralized mortgage obligations | 1,847,048 |
| | 23,754 |
| | 217,245 |
| | 3,882 |
| | 2,064,293 |
| | 27,636 |
| Total temporarily impaired securities | $ | 1,879,729 |
| | $ | 24,570 |
| | $ | 223,432 |
| | $ | 4,125 |
| | $ | 2,103,161 |
| | $ | 28,695 |
|
| | | | | | | | | | | | | | | | | | | | | | | | | December 31, 2016 | | | | | | | | | | | | (in thousands) | Less than 12 Months | | 12 Months or Longer | | Total | | Fair | | Unrealized | | Fair | | Unrealized | | Fair | | Unrealized | | Value | | Losses | | Value | | Losses | | Value | | Losses | AVAILABLE FOR SALE: | |
| | |
| | |
| | |
| | |
| | |
| Obligations of states and political subdivisions | $ | 71,571 |
| | $ | 3,065 |
| | $ | 1,828 |
| | $ | 472 |
| | $ | 73,399 |
| | $ | 3,537 |
| Residential mortgage-backed securities and collateralized mortgage obligations | 1,855,304 |
| | 35,981 |
| | 182,804 |
| | 4,517 |
| | 2,038,108 |
| | 40,498 |
| Total temporarily impaired securities | $ | 1,926,875 |
| | $ | 39,046 |
| | $ | 184,632 |
| | $ | 4,989 |
| | $ | 2,111,507 |
| | $ | 44,035 |
|
The unrealized losses on obligations of states and political subdivisions were caused by changes in market interest rates or the widening of market spreads subsequent to the initial purchase of these securities. Management monitors the published credit ratings of these securities for material rating or outlook changes. As of June 30, 2017, 93% of these securities were rated A3/A- or higher by rating agencies. Substantially all of the Company's obligations of states and political subdivisions are general obligation issuances. All of the available for sale residential mortgage-backed securities and collateralized mortgage obligations portfolio in an unrealized loss position at June 30, 2017 are issued or guaranteed by government sponsored enterprises. The unrealized losses on residential mortgage-backed securities and collateralized mortgage obligations were caused by changes in market interest rates or the widening of market spreads subsequent to the initial purchase of these securities, and not concerns regarding the underlying credit of the issuers or the underlying collateral. It is expected that these securities will be settled at a price at least equal to the amortized cost of each investment.
Because the decline in fair value is attributable to changes in interest rates or widening market spreads and not credit quality, and because the Bank does not intend to sell the securities and it is not more likely than not that the Bank will be required to sell these securities before recovery of their amortized cost basis, which may include holding each security until maturity, these investments are not considered other-than-temporarily impaired.
The following table presents the maturities of investment securities at June 30, 2017: | | | | | | | | | | | | | | | | | (in thousands) | Available For Sale | | Held To Maturity | | Amortized | | Fair | | Amortized | | Fair | | Cost | | Value | | Cost | | Value | AMOUNTS MATURING IN: | | | | | | | | Three months or less | $ | 722 |
| | $ | 724 |
| | $ | — |
| | $ | — |
| Over three months through twelve months | 1,272 |
| | 1,281 |
| | — |
| | — |
| After one year through five years | 58,973 |
| | 59,861 |
| | — |
| | — |
| After five years through ten years | 406,007 |
| | 409,846 |
| | 19 |
| | 20 |
| After ten years | 2,680,038 |
| | 2,658,873 |
| | 3,998 |
| | 5,051 |
| Other investment securities | 1,959 |
| | 1,981 |
| | — |
| | — |
| | $ | 3,148,971 |
| | $ | 3,132,566 |
| | $ | 4,017 |
| | $ | 5,071 |
|
The following tables present the gross realized gains and losses on the sale of securities available for sale for the three and six months ended June 30, 2017 and 2016:
| | | | | | | | | | | | | | | | | (in thousands) | Three Months Ended | | June 30, 2017 | | June 30, 2016 | | Gains | | Losses | | Gains | | Losses | Obligations of states and political subdivisions | $ | — |
| | $ | 1 |
| | $ | 275 |
| | $ | — |
| Residential mortgage-backed securities and collateralized mortgage obligations | 135 |
| | 99 |
| | 270 |
| | 383 |
| | $ | 135 |
| | $ | 100 |
| | $ | 545 |
| | $ | 383 |
| | | | | | | | | | Six Months Ended | | June 30, 2017 | | June 30, 2016 | | Gains | | Losses | | Gains | | Losses | Obligations of states and political subdivisions | $ | — |
| | $ | 3 |
| | $ | 971 |
| | $ | — |
| Residential mortgage-backed securities and collateralized mortgage obligations | 135 |
| | 99 |
| | 270 |
| | 383 |
| | $ | 135 |
| | $ | 102 |
| | $ | 1,241 |
| | $ | 383 |
|
The following table presents, as of June 30, 2017, investment securities which were pledged to secure borrowings, public deposits, and repurchase agreements as permitted or required by law: | | | | | | | | | (in thousands) | Amortized | | Fair | | Cost | | Value | To the Federal Home Loan Bank to secure borrowings | $ | 502 |
| | $ | 511 |
| To state and local governments to secure public deposits | 931,950 |
| | 932,534 |
| Other securities pledged principally to secure repurchase agreements | 423,380 |
| | 420,042 |
| Total pledged securities | $ | 1,355,832 |
| | $ | 1,353,087 |
|
|