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Investment Securities (Tables) | 6 Months Ended
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Jun. 30, 2022
Investment Securities |
Schedule of amortized cost of investment securities to estimated fair values | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | June 30, 2022
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
(dollars in thousands) |  | Cost | ​ | Gains | ​ | Losses |  | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury and agencies | ​ | $ | 3,643 | ​ | $ | 66 | ​ | $ | — | ​ | $ | 3,709
Mortgage backed securities | ​ |  |  | ​ |  | ​ | ​ |  | ​ | ​ |  | ​
Residential agency | ​ |  | 740,734 | ​ |  | 27 | ​ |  | (88,254) | ​ |  | 652,507
Commercial | ​ |  | 80,077 | ​ |  | — | ​ |  | (3,947) | ​ |  | 76,130
Asset backed securities | ​ |  | 40 | ​ |  | — | ​ |  | — | ​ |  | 40
Corporate bonds | ​ |  | 69,031 | ​ |  | 130 | ​ |  | (2,750) | ​ |  | 66,411
Total available-for-sale investment securities | ​ | ​ | 893,525 | ​ | ​ | 223 | ​ | ​ | (94,951) | ​ | ​ | 798,797
Held-to-maturity | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Obligations of state and political agencies | ​ | ​ | 139,102 | ​ |  | 2 | ​ |  | (12,927) | ​ |  | 126,177
Mortgage backed securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Residential agency | ​ | ​ | 192,639 | ​ |  | — | ​ |  | (24,867) | ​ |  | 167,772
Total held-to-maturity investment securities | ​ | ​ | 331,741 | ​ | ​ | 2 | ​ | ​ | (37,794) | ​ | ​ | 293,949
Total investment securities | ​ | $ | 1,225,266 | ​ | $ | 225 | ​ | $ | (132,745) | ​ | $ | 1,092,746
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2021
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
(dollars in thousands) |  | Cost | ​ | Gains | ​ | Losses |  | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury and agencies | ​ | $ | 5,028 | ​ | $ | 75 | ​ | $ | — | ​ | $ | 5,103
Mortgage backed securities | ​ |  |  | ​ |  | ​ | ​ |  | ​ | ​ |  |
Residential agency | ​ |  | 717,781 | ​ |  | 1,213 | ​ |  | (11,837) | ​ |  | 707,157
Commercial | ​ |  | 88,362 | ​ |  | 2,674 | ​ |  | (123) | ​ |  | 90,913
Asset backed securities | ​ |  | 52 | ​ | ​ | 2 | ​ |  | — | ​ |  | 54
Corporate bonds | ​ |  | 49,035 | ​ |  | 1,398 | ​ |  | (11) | ​ |  | 50,422
Total available-for-sale investment securities | ​ | ​ | 860,258 | ​ | ​ | 5,362 | ​ | ​ | (11,971) | ​ | ​ | 853,649
Held-to-maturity | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Obligations of state and political agencies | ​ | ​ | 144,543 | ​ | ​ | 1,110 | ​ | ​ | (349) | ​ | ​ | 145,304
Mortgage backed securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Residential agency | ​ | ​ | 207,518 | ​ | ​ | — | ​ | ​ | (3,145) | ​ | ​ | 204,373
Total held-to-maturity investment securities | ​ | ​ | 352,061 | ​ | ​ | 1,110 | ​ | ​ | (3,494) | ​ | ​ | 349,677
Total investment securities | ​ | $ | 1,212,319 | ​ | $ | 6,472 | ​ | $ | (15,465) | ​ | $ | 1,203,326
Schedule of investment securities with gross unrealized losses | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | June 30, 2022
​ | ​ | Less than 12 Months | ​ | Over 12 Months | ​ | Total
​ | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair
(dollars in thousands) |  | Losses |  | Value |  | Losses |  | Value |  | Losses |  | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury and agencies | ​ | $ | — | ​ | $ | — | ​ | $ | — | ​ | $ | — | ​ | $ | — | ​ | $ | —
Mortgage backed securities | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |
Residential agency | ​ |  | (51,859) | ​ |  | 436,234 | ​ |  | (36,395) | ​ |  | 214,079 | ​ |  | (88,254) | ​ |  | 650,313
Commercial | ​ |  | (3,947) | ​ |  | 76,130 | ​ |  | — | ​ |  | — | ​ |  | (3,947) | ​ |  | 76,130
Asset backed securities | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | 2 | ​ |  | — | ​ |  | 2
Corporate bonds | ​ |  | (2,750) | ​ |  | 56,780 | ​ |  | — | ​ |  | — | ​ |  | (2,750) | ​ |  | 56,780
Total available-for-sale investment securities | ​ | ​ | (58,556) | ​ | ​ | 569,144 | ​ | ​ | (36,395) | ​ | ​ | 214,081 | ​ | ​ | (94,951) | ​ | ​ | 783,225
Held-to-maturity | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Obligations of state and political agencies | ​ | ​ | (12,927) | ​ | ​ | 122,734 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | (12,927) | ​ | ​ | 122,734
Mortgage backed securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Residential agency | ​ | ​ | (24,867) | ​ | ​ | 167,772 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | (24,867) | ​ | ​ | 167,772
Total held-to-maturity investment securities | ​ | ​ | (37,794) | ​ | ​ | 290,506 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | (37,794) | ​ | ​ | 290,506
Total investment securities | ​ | $ | (96,350) | ​ | $ | 859,650 | ​ | $ | (36,395) | ​ | $ | 214,081 | ​ | $ | (132,745) | ​ | $ | 1,073,731
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2021
​ | ​ | Less than 12 Months | ​ | Over 12 Months | ​ | Total
​ | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair
(dollars in thousands) |  | Losses |  | Value |  | Losses |  | Value |  | Losses |  | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury and agencies | ​ | $ | — | ​ | $ | — | ​ | $ | — | ​ | $ | — | ​ | $ | — | ​ | $ | —
Mortgage backed securities | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |
Residential agency | ​ |  | (10,156) | ​ |  | 554,811 | ​ |  | (1,681) | ​ |  | 55,082 | ​ |  | (11,837) | ​ |  | 609,893
Commercial | ​ |  | (123) | ​ |  | 17,470 | ​ |  | — | ​ |  | — | ​ |  | (123) | ​ |  | 17,470
Asset backed securities | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | 2 | ​ |  | — | ​ |  | 2
Corporate bonds | ​ |  | (11) | ​ |  | 5,989 | ​ |  | — | ​ |  | — | ​ |  | (11) | ​ |  | 5,989
Total available-for-sale investment securities | ​ | ​ | (10,290) | ​ | ​ | 578,270 | ​ | ​ | (1,681) | ​ | ​ | 55,084 | ​ | ​ | (11,971) | ​ | ​ | 633,354
Held-to-maturity | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Obligations of state and political agencies | ​ | ​ | (349) | ​ | ​ | 53,210 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | (349) | ​ | ​ | 53,210
Mortgage backed securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Residential agency | ​ | ​ | (3,145) | ​ | ​ | 204,373 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | (3,145) | ​ | ​ | 204,373
Total held-to-maturity investment securities | ​ | ​ | (3,494) | ​ | ​ | 257,583 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | (3,494) | ​ | ​ | 257,583
Total investment securities | ​ | $ | (13,784) | ​ | $ | 835,853 | ​ | $ | (1,681) | ​ | $ | 55,084 | ​ | $ | (15,465) | ​ | $ | 890,937
Schedule of contractual maturity of amortized cost and estimated fair value | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Held-to-maturity | ​ | Available-for-sale
​ | ​ | Carrying | ​ | Fair | ​ | Amortized | ​ | Fair
(dollars in thousands) |  | Value | ​ | Value | ​ | Cost |  | Value
Due within one year or less | ​ | $ | 6,831 | ​ | $ | 6,794 | ​ | $ | 20 | ​ | $ | 21
Due after one year through five years | ​ |  | 36,025 | ​ |  | 33,922 | ​ |  | 21,599 | ​ |  | 21,017
Due after five years through ten years | ​ |  | 72,720 | ​ |  | 65,003 | ​ |  | 94,957 | ​ |  | 91,522
Due after 10 years | ​ |  | 216,165 | ​ |  | 188,230 | ​ |  | 776,949 | ​ |  | 686,237
Total investment securities | ​ | $ | 331,741 | ​ | $ | 293,949 | ​ | $ | 893,525 | ​ | $ | 798,797
Schedule of proceeds from the sale of available for sale securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Three months ended | ​ | Six months ended
​ | ​ | June 30, | ​ | June 30,
(dollars in thousands) |  | 2022 |  | 2021 |  | 2022 |  | 2021
Proceeds | ​ | $ | — | ​ | $ | — | ​ | $ | — | ​ | $ | 13,189
Realized gains | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | 114
Realized losses | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | —
Schedule of proceeds from the call of held-to-maturity investment securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Three months ended | ​ | Six months ended
​ | ​ | June 30, | ​ | June 30,
(dollars in thousands) |  | 2022 |  | 2021 |  | 2022 |  | 2021
Proceeds | ​ | $ | 211 | ​ | $ | — | ​ | $ | 726 | ​ | $ | 1,415
Realized gains | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | —
Realized losses | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | —
​
Schedule of federal home loan bank | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | June 30, | ​ | December 31,
(dollars in thousands) |  | 2022 |  | 2021
Federal Reserve | ​ | $ | 2,675 | ​ | $ | 2,675
FHLB | ​ |  | 13,938 | ​ |  | 3,806

X
- Definition Tabular disclosure of fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale and held-to-maturity), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References No definition available. + Details
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- Definition Tabular disclosure of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale). + References Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -URI http://asc.fasb.org/topic&trid=2196928 + Details
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