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Investment Securities (Tables) | 12 Months Ended
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Dec. 31, 2020
Investments, Debt and Equity Securities [Abstract] |
Investment Securities, At Fair Value | Investment securities, at fair value, consisted of the following at December 31, 2020 and 2019:
(In thousands) | 2020 | 2019
Available for sale debt securities | $ | 12,449,264 |  | $ | 8,571,626 |
Trading debt securities | 35,321 |  | 28,161 |
Equity securities: |  |
Readily determinable fair value | 2,966 |  | 2,929 |
No readily determinable fair value | 1,397 |  | 1,280 |
Other: |  |
Federal Reserve Bank stock | 34,070 |  | 33,770 |
Federal Home Loan Bank stock | 10,307 |  | 10,000 |
Equity method investments | 18,000 |  | — |
Private equity investments | 94,368 |  | 94,122 |
Total investment securities (1) | $ | 12,645,693 |  | $ | 8,741,888 |
(1) Accrued interest receivable totaled $41.5 million at December 31, 2020 and was included within other assets on the consolidated balance sheet.
Summary Of Available For Sale Investment Securities By Maturity Groupings |
(Dollars in thousands) | Amortized Cost | Fair Value | Weighted Average Yield
U.S. government and federal agency obligations: |  |  |
Within 1 year | $ | 59,627 |  | $ | 59,641 |  | .90 | *%
After 1 but within 5 years | 490,333 |  | 521,540 |  | 2.22 | *
After 5 but within 10 years | 225,632 |  | 256,878 |  | .65 | *
Total U.S. government and federal agency obligations | 775,592 |  | 838,059 |  | 1.66 | *
Government-sponsored enterprise obligations: |  |  |
Within 1 year | 14,993 |  | 14,916 |  | 2.15 |
After 10 years | 35,810 |  | 39,569 |  | 2.39 |
Total government-sponsored enterprise obligations | 50,803 |  | 54,485 |  | 2.32 |
State and municipal obligations: |  |  |
Within 1 year | 34,694 |  | 34,866 |  | 2.35 |
After 1 but within 5 years | 865,165 |  | 901,201 |  | 2.20 |
After 5 but within 10 years | 595,510 |  | 627,063 |  | 2.01 |
After 10 years | 472,637 |  | 481,969 |  | 1.84 |
Total state and municipal obligations | 1,968,006 |  | 2,045,099 |  | 2.06 |
Mortgage and asset-backed securities: |  |  |
Agency mortgage-backed securities | 6,557,098 |  | 6,712,085 |  | 2.00 |
Non-agency mortgage-backed securities | 358,074 |  | 361,074 |  | 2.39 |
Asset-backed securities | 1,853,791 |  | 1,882,243 |  | 1.53 |
Total mortgage and asset-backed securities | 8,768,963 |  | 8,955,402 |  | 1.92 |
Other debt securities: |  |  |
Within 1 year | 8,041 |  | 8,118 |  |
After 1 but within 5 years | 254,173 |  | 265,486 |  |
After 5 but within 10 years | 240,759 |  | 250,036 |  |
After 10 years | 31,196 |  | 32,579 |  |
Total other debt securities | 534,169 |  | 556,219 |  |
Total available for sale debt securities | $ | 12,097,533 |  | $ | 12,449,264 |  |
* Rate does not reflect inflation adjustment on inflation-protected securities
Cash Flow Model Inputs Used To Calculate Credit Losses | Significant inputs to the cash flow model used at December 31, 2020 to quantify credit losses were primarily credit support agreements, as the securities on the Company's watch list at December 31, 2020 were securities backed by government-guaranteed student loans and are expected to perform as contractually required. As of December 31, 2020, the Company did not identify any securities for which a credit loss exists.
Securities With Unrealized Losses And Length Of Impairment Period |
| Less than 12 months |  | 12 months or longer |  | Total
(In thousands) | Fair Value | Unrealized Losses |  | Fair Value | Unrealized Losses |  | Fair Value | Unrealized Losses
December 31, 2020 |  |  |  |  |  |  |  |
Government-sponsored enterprise obligations | $ | 19,720 |  | $ | 98 |  |  | $ | — |  | $ | — |  |  | $ | 19,720 |  | $ | 98 |
State and municipal obligations | 45,622 |  | 230 |  |  | — |  | — |  |  | 45,622 |  | 230 |
Mortgage and asset-backed securities: |  |  |  |  |  |  |  |
Agency mortgage-backed securities | 470,373 |  | 2,802 |  |  | — |  | — |  |  | 470,373 |  | 2,802 |
Non-agency mortgage-backed securities | 112,861 |  | 380 |  |  | — |  | — |  |  | 112,861 |  | 380 |
Asset-backed securities | 21,360 |  | 56 |  |  | 253,734 |  | 2,617 |  |  | 275,094 |  | 2,673 |
Total mortgage and asset-backed securities | 604,594 |  | 3,238 |  |  | 253,734 |  | 2,617 |  |  | 858,328 |  | 5,855 |
Other debt securities | 24,522 |  | 175 |  |  | — |  | — |  |  | 24,522 |  | 175 |
Total | $ | 694,458 |  | $ | 3,741 |  |  | $ | 253,734 |  | $ | 2,617 |  |  | $ | 948,192 |  | $ | 6,358 |
Debt securities available for sale in an unrealized loss position, aggregated by major security type and length of impairment period, are as follows:
| Less than 12 months |  | 12 months or longer |  | Total
(In thousands) | Fair Value | Unrealized Losses |  | Fair Value | Unrealized Losses |  | Fair Value | Unrealized Losses
December 31, 2019 |  |  |  |  |  |  |  |
U.S. government and federal agency obligations | $ | 31,787 |  | $ | 21 |  |  | $ | 25,405 |  | $ | 21 |  |  | $ | 57,192 |  | $ | 42 |
Government-sponsored enterprise obligations | 6,155 |  | 187 |  |  | — |  | — |  |  | 6,155 |  | 187 |
State and municipal obligations | 6,700 |  | 31 |  |  | 1,554 |  | 1 |  |  | 8,254 |  | 32 |
Mortgage and asset-backed securities: |  |  |  |  |  |  |  |
Agency mortgage-backed securities | 652,352 |  | 5,306 |  |  | 147,653 |  | 867 |  |  | 800,005 |  | 6,173 |
Non-agency mortgage-backed securities | 102,931 |  | 254 |  |  | 189,747 |  | 451 |  |  | 292,678 |  | 705 |
Asset-backed securities | 330,876 |  | 3,610 |  |  | 152,461 |  | 2,108 |  |  | 483,337 |  | 5,718 |
Total mortgage and asset-backed securities | 1,086,159 |  | 9,170 |  |  | 489,861 |  | 3,426 |  |  | 1,576,020 |  | 12,596 |
Other debt securities | 5,496 |  | 4 |  |  | 997 |  | 3 |  |  | 6,493 |  | 7 |
Total | $ | 1,136,297 |  | $ | 9,413 |  |  | $ | 517,817 |  | $ | 3,451 |  |  | $ | 1,654,114 |  | $ | 12,864 |
Available For Sale Securities Unrealized Gains And Losses By Security Type | For debt securities classified as available for sale, the following table shows the amortized cost, fair value, and allowance for credit losses of securities available for sale at December 31, 2020 and the corresponding amounts of gross unrealized gains and losses (pre-tax) in AOCI, by security type.
(In thousands) | Amortized Cost | Gross Unrealized Gains | Gross Unrealized Losses | Allowance for Credit Losses | Fair Value
December 31, 2020 |  |  |  |  |
U.S. government and federal agency obligations | $ | 775,592 |  | $ | 62,467 |  | $ | — |  | $ | — |  | $ | 838,059 |
Government-sponsored enterprise obligations | 50,803 |  | 3,780 |  | (98) |  | — |  | 54,485 |
State and municipal obligations | 1,968,006 |  | 77,323 |  | (230) |  | — |  | 2,045,099 |
Mortgage and asset-backed securities: |  |  |  |  |
Agency mortgage-backed securities | 6,557,098 |  | 157,789 |  | (2,802) |  | — |  | 6,712,085 |
Non-agency mortgage-backed securities | 358,074 |  | 3,380 |  | (380) |  | — |  | 361,074 |
Asset-backed securities | 1,853,791 |  | 31,125 |  | (2,673) |  | — |  | 1,882,243 |
Total mortgage and asset-backed securities | 8,768,963 |  | 192,294 |  | (5,855) |  | — |  | 8,955,402 |
Other debt securities | 534,169 |  | 22,225 |  | (175) |  | — |  | 556,219 |
Total | $ | 12,097,533 |  | $ | 358,089 |  | $ | (6,358) |  | $ | — |  | $ | 12,449,264 |
For debt securities classified as available for sale, the following table shows the amortized cost and fair value of securities available for sale at December 31, 2019 and the corresponding amounts of gross unrealized gains and losses (pre-tax) in AOCI, by security type.
(In thousands) | Amortized Cost | Gross Unrealized Gains | Gross Unrealized Losses | Fair Value
December 31, 2019 |  |  |  |
U.S. government and federal agency obligations | $ | 827,861 |  | $ | 23,957 |  | $ | (42) |  | $ | 851,776 |
Government-sponsored enterprise obligations | 138,734 |  | 730 |  | (187) |  | 139,277 |
State and municipal obligations | 1,225,532 |  | 42,427 |  | (32) |  | 1,267,927 |
Mortgage and asset-backed securities: |  |  |  |
Agency mortgage-backed securities | 3,893,247 |  | 50,890 |  | (6,173) |  | 3,937,964 |
Non-agency mortgage-backed securities | 796,451 |  | 14,036 |  | (705) |  | 809,782 |
Asset-backed securities | 1,228,151 |  | 11,056 |  | (5,718) |  | 1,233,489 |
Total mortgage and asset-backed securities | 5,917,849 |  | 75,982 |  | (12,596) |  | 5,981,235 |
Other debt securities | 325,555 |  | 5,863 |  | (7) |  | 331,411 |
Total | $ | 8,435,531 |  | $ | 148,959 |  | $ | (12,864) |  | $ | 8,571,626 |
Proceeds From Sales Of Securities And Components Of Investment Securities Gains And Losses | The following table presents proceeds from sales of securities and the components of investment securities gains and losses which have been recognized in earnings.
| For the Year Ended December 31
(In thousands) | 2020 | 2019 | 2018
Proceeds from sales of securities: |  |  |
Available for sale debt securities | $ | 602,475 |  | $ | 402,103 |  | $ | 667,227 |
Equity securities | 2 |  | 3,856 |  | 41,637 |
Other | — |  | 7,244 |  | — |
Total proceeds | $ | 602,477 |  | $ | 413,203 |  | $ | 708,864 |
Investment securities gains (losses), net: |  |  |
Available for sale debt securities: |  |  |
Gains realized on sales | $ | 21,096 |  | $ | 2,354 |  | $ | 448 |
Losses realized on sales | — |  | (2,568) |  | (10,101) |
Other-than-temporary impairment recognized on debt securities | — |  | (133) |  | (68) |
Equity securities: |  |  |
Gains realized on sales | 2 |  | 3,262 |  | 1,759 |
Losses realized on sales | — |  | — |  | (8,917) |
Fair value adjustments, net | 37 |  | 344 |  | 2,542 |
Other: |  |  |
Gains realized on sales | — |  | 1,094 |  | — |
Fair value adjustments, net | (10,103) |  | (727) |  | 13,849 |
Total investment securities gains (losses), net | $ | 11,032 |  | $ | 3,626 |  | $ | (488) |

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