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Securities (Tables) | 12 Months Ended
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Dec. 31, 2021
Securities |
Schedule of amortized cost and fair value of the securities portfolio and corresponding amounts of gross unrealized gains and losses recognized in accumulated other comprehensive loss | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
December 31, 2021 |  | Cost1 |  | Gains |  | Losses | ​ | Value
Securities available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury | ​ | $ | 202,251 | ​ | $ | 125 | ​ | $ | (37) | ​ | $ | 202,339
U.S. government agencies | ​ | ​ | 62,587 | ​ | ​ | - | ​ | ​ | (699) | ​ | ​ | 61,888
U.S. government agencies mortgage-backed | ​ | ​ | 172,016 | ​ | ​ | 856 | ​ | ​ | (570) | ​ | ​ | 172,302
States and political subdivisions | ​ | ​ | 240,793 | ​ | ​ | 16,344 | ​ | ​ | (672) | ​ | ​ | 256,465
Corporate bonds | ​ | ​ | 10,000 | ​ | ​ | - | ​ | ​ | (113) | ​ | ​ | 9,887
Collateralized mortgage obligations | ​ | ​ | 673,238 | ​ | ​ | 2,014 | ​ | ​ | (2,285) | ​ | ​ | 672,967
Asset-backed securities | ​ | ​ | 236,293 | ​ | ​ | 1,245 | ​ | ​ | (661) | ​ | ​ | 236,877
Collateralized loan obligations | ​ | ​ | 79,838 | ​ | ​ | 3 | ​ | ​ | (78) | ​ | ​ | 79,763
Total securities available-for-sale | ​ | $ | 1,677,016 | ​ | $ | 20,587 | ​ | $ | (5,115) | ​ | $ | 1,692,488
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
December 31, 2020 |  | Cost1 |  | Gains |  | Losses | ​ | Value
Securities available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury | ​ | $ | 4,014 | ​ | $ | 103 | ​ | $ | - | ​ | $ | 4,117
U.S. government agencies | ​ | ​ | 6,811 | ​ | ​ | - | ​ | ​ | (154) | ​ | ​ | 6,657
U.S. government agencies mortgage-backed | ​ | ​ | 16,098 | ​ | ​ | 1,112 | ​ | ​ | (1) | ​ | ​ | 17,209
States and political subdivisions | ​ | ​ | 229,352 | ​ | ​ | 21,269 | ​ | ​ | (1,362) | ​ | ​ | 249,259
Collateralized mortgage obligations | ​ | ​ | 53,999 | ​ | ​ | 2,866 | ​ | ​ | (280) | ​ | ​ | 56,585
Asset-backed securities | ​ | ​ | 130,959 | ​ | ​ | 1,370 | ​ | ​ | (511) | ​ | ​ | 131,818
Collateralized loan obligations | ​ | ​ | 30,728 | ​ | ​ | 15 | ​ | ​ | (210) | ​ | ​ | 30,533
Total securities available-for-sale | ​ | $ | 471,961 | ​ | $ | 26,735 | ​ | $ | (2,518) | ​ | $ | 496,178
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
1 Excludes interest receivable of $4.3 million and $2.7 million at December 31, 2021 and December 31, 2020, respectively, that is recorded in other assets on the consolidated balance sheet. ​
Schedule of fair value, amortized cost and weighted average yield of debt securities by contractual maturity along with securities not due at a single maturity date, primarily mortgage-backed securities (MBS), asset-backed securities, and collateralized loan obligations | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | ​ | Weighted | ​ | ​ | ​ | ​ | ​
​ | ​ | Amortized | ​ | Average | ​ | ​ | Fair | ​
Securities available-for-sale |  | Cost |  | Yield | ​ |  | Value |
Due in one year or less | ​ | $ | 8,671 | ​ | 1.24 | % | ​ | $ | 8,707 | ​
Due after one year through five years | ​ | ​ | 274,984 | ​ | 0.89 | ​ | ​ | ​ | 274,537 | ​
Due after five years through ten years | ​ | ​ | 43,770 | ​ | 2.43 | ​ | ​ | ​ | 45,470 | ​
Due after ten years | ​ | ​ | 188,206 | ​ | 2.98 | ​ | ​ | ​ | 201,865 | ​
​ | ​ | ​ | 515,631 | ​ | 1.79 | ​ | ​ | ​ | 530,579 | ​
Mortgage-backed and collateralized mortgage obligations | ​ | ​ | 845,254 | ​ | 1.19 | ​ | ​ | ​ | 845,269 | ​
Asset-backed securities | ​ | ​ | 236,293 | ​ | 1.12 | ​ | ​ | ​ | 236,877 | ​
Collateralized loan obligations | ​ | ​ | 79,838 | ​ | 1.60 | ​ | ​ | ​ | 79,763 | ​
Total securities available-for-sale | ​ | $ | 1,677,016 | ​ | 1.38 | % | ​ | $ | 1,692,488 | ​
Schedule of securities with unrealized losses aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position | Securities with unrealized losses with no corresponding allowance for credit losses at December 31, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, were as follows (in thousands except for number of securities): ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Less than 12 months | ​ | 12 months or more | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
December 31, 2021 | ​ | in an unrealized loss position | ​ | in an unrealized loss position | ​ | Total
​ | ​ | Number of | ​ | Unrealized | ​ | Fair | ​ | Number of | ​ | Unrealized | ​ | Fair | ​ | Number of | ​ | Unrealized | ​ | Fair
Securities available-for-sale |  | Securities |  | Losses |  | Value |  | Securities |  | Losses |  | Value |  | Securities |  | Losses |  | Value
U.S. Treasuries | ​ | 1 | ​ | $ | 37 | ​ | $ | 49,719 | ​ | - | ​ | $ | - | ​ | $ | - | ​ | 1 | ​ | $ | 37 | ​ | $ | 49,719
U.S. government agencies | ​ | 5 | ​ | $ | 592 | ​ | $ | 56,879 | ​ | 4 | ​ | $ | 107 | ​ | $ | 5,008 | ​ | 9 | ​ | $ | 699 | ​ | $ | 61,887
U.S. government agencies mortgage-backed | ​ | 63 | ​ | ​ | 505 | ​ | ​ | 78,711 | ​ | 1 | ​ | ​ | 65 | ​ | ​ | 1,663 | ​ | 64 | ​ | ​ | 570 | ​ | ​ | 80,374
States and political subdivisions | ​ | 7 | ​ | ​ | 55 | ​ | ​ | 8,430 | ​ | 1 | ​ | ​ | 617 | ​ | ​ | 4,051 | ​ | 8 | ​ | ​ | 672 | ​ | ​ | 12,481
Corporate bonds | ​ | 2 | ​ | ​ | 113 | ​ | ​ | 9,887 | ​ | - | ​ | ​ | - | ​ | ​ | - | ​ | 2 | ​ | ​ | 113 | ​ | ​ | 9,887
Collateralized mortgage obligations | ​ | 133 | ​ | ​ | 2,285 | ​ | ​ | 381,658 | ​ | - | ​ | ​ | - | ​ | ​ | - | ​ | 133 | ​ | ​ | 2,285 | ​ | ​ | 381,658
Asset-backed securities | ​ | 20 | ​ | ​ | 608 | ​ | ​ | 103,819 | ​ | 3 | ​ | ​ | 53 | ​ | ​ | 3,276 | ​ | 23 | ​ | ​ | 661 | ​ | ​ | 107,095
Collateralized loan obligations | ​ | 10 | ​ | ​ | 35 | ​ | ​ | 45,132 | ​ | 2 | ​ | ​ | 43 | ​ | ​ | 10,628 | ​ | 12 | ​ | ​ | 78 | ​ | ​ | 55,760
Total securities available-for-sale | ​ | 241 | ​ | $ | 4,230 | ​ | $ | 734,235 | ​ | 11 | ​ | $ | 885 | ​ | $ | 24,626 | ​ | 252 | ​ | $ | 5,115 | ​ | $ | 758,861
​ ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Less than 12 months | ​ | 12 months or more | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
December 31, 2020 | ​ | in an unrealized loss position | ​ | in an unrealized loss position | ​ | Total
​ | ​ | Number of | ​ | Unrealized | ​ | ​ | Fair | ​ | Number of | ​ | Unrealized | ​ | ​ | Fair | ​ | Number of | ​ | Unrealized | ​ | ​ | Fair
Securities available-for-sale |  | Securities |  | Losses |  | ​ | Value |  | Securities |  | Losses |  | ​ | Value |  | Securities |  | Losses |  | ​ | Value
U.S. government agencies | ​ | - | ​ | $ | - | ​ | $ | - | ​ | 4 | ​ | $ | 154 | ​ | $ | 6,657 | ​ | 4 | ​ | $ | 154 | ​ | $ | 6,657
U.S. government agencies mortgage-backed | ​ | 1 | ​ | ​ | 1 | ​ | ​ | 141 | ​ | - | ​ | ​ | - | ​ | ​ | - | ​ | 1 | ​ | ​ | 1 | ​ | ​ | 141
States and political subdivisions | ​ | - | ​ | ​ | - | ​ | ​ | - | ​ | 1 | ​ | ​ | 1,362 | ​ | ​ | 3,433 | ​ | 1 | ​ | ​ | 1,362 | ​ | ​ | 3,433
Collateralized mortgage obligations | ​ | 4 | ​ | ​ | 279 | ​ | ​ | 8,142 | ​ | 1 | ​ | ​ | 1 | ​ | ​ | 146 | ​ | 5 | ​ | ​ | 280 | ​ | ​ | 8,288
Asset-backed securities | ​ | 1 | ​ | ​ | 2 | ​ | ​ | 251 | ​ | 3 | ​ | ​ | 509 | ​ | ​ | 49,572 | ​ | 4 | ​ | ​ | 511 | ​ | ​ | 49,823
Collateralized loan obligations | ​ | 1 | ​ | ​ | 31 | ​ | ​ | 7,468 | ​ | 4 | ​ | ​ | 179 | ​ | ​ | 21,477 | ​ | 5 | ​ | ​ | 210 | ​ | ​ | 28,945
Total securities available-for-sale | ​ | 7 | ​ | $ | 313 | ​ | $ | 16,002 | ​ | 13 | ​ | $ | 2,205 | ​ | $ | 81,285 | ​ | 20 | ​ | $ | 2,518 | ​ | $ | 97,287
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Schedule of proceeds from sale and gross realized gains and losses on sale of securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year Ended | ​
​ | ​ | December 31, | ​
Securities available-for-sale |  | 2021 |  | 2020 |  | 2019 | ​
Proceeds from sales of securities | ​ | $ | 605,846 | ​ | $ | 18,006 | ​ | $ | 191,298 | ​
Gross realized gains on securities | ​ |  | 270 | ​ |  | 17 | ​ |  | 5,521 | ​
Gross realized losses on securities | ​ |  | (38) | ​ |  | (42) | ​ |  | (1,010) | ​
Net realized gains (losses) | ​ | $ | 232 | ​ | $ | (25) | ​ | $ | 4,511 | ​
Income tax (expense) benefit on net realized gains (losses) | ​ | $ | (65) | ​ | $ | 7 | ​ | $ | (1,267) | ​
Effective tax rate applied | ​ | ​ | 28.0 | % | ​ | 28.0 | % | ​ | 28.1 | %

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- Definition Tabular disclosure of the proceeds from sales of available-for-sale securities and the gross realized gains and gross realized losses that have been included in earnings as a result of those sales. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27357-111563 + Details
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- Definition For all investments in an unrealized loss position, including those for which other-than-temporary impairments have not been recognized in earnings (including investments for which a portion of an other-than-temporary impairment has been recognized in other comprehensive income), a tabular disclosure of the aggregate related fair value of investments with unrealized losses and the aggregate amount of unrealized losses (that is, the amount by which amortized cost basis exceeds fair value). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 6 -URI http://asc.fasb.org/extlink&oid=123581744&loc=d3e27290-111563 + Details
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