XML 65 R42.htm IDEA: XBRL DOCUMENT
v3.24.0.1

Investment Securities (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2023
Investment Securities |
Schedule of amortized cost of investment securities to estimated fair values | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2023
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Allowance for | ​ | Fair
(dollars in thousands) |  | Cost | ​ | Gains | ​ | Losses | ​ | Credit Losses |  | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury and agencies | ​ | $ | 1,119 | ​ | $ | 4 | ​ | $ | (3) | ​ | $ | — | ​ | $ | 1,120
Mortgage backed securities | ​ |  |  | ​ |  | ​ | ​ |  | ​ | ​ | ​ | ​ | ​ |  | ​
Residential agency | ​ |  | 524,140 | ​ |  | 1 | ​ |  | (88,547) | ​ | ​ | — | ​ |  | 435,594
Commercial | ​ |  | 1,476 | ​ |  | — | ​ |  | (123) | ​ | ​ | — | ​ |  | 1,353
Asset backed securities | ​ |  | 26 | ​ |  | — | ​ |  | (1) | ​ | ​ | — | ​ |  | 25
Corporate bonds | ​ |  | 57,993 | ​ |  | — | ​ |  | (9,349) | ​ | ​ | — | ​ |  | 48,644
Total available-for-sale investment securities | ​ | ​ | 584,754 | ​ | ​ | 5 | ​ | ​ | (98,023) | ​ | ​ | — | ​ | ​ | 486,736
Held-to-maturity | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Obligations of state and political agencies | ​ | ​ | 129,603 | ​ |  | — | ​ |  | (12,613) | ​ | ​ | 114 | ​ |  | 116,990
Mortgage backed securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Residential agency | ​ | ​ | 170,125 | ​ |  | — | ​ |  | (28,498) | ​ | ​ | 99 | ​ |  | 141,627
Total held-to-maturity investment securities | ​ | ​ | 299,728 | ​ | ​ | — | ​ | ​ | (41,111) | ​ | ​ | 213 | ​ | ​ | 258,617
Total investment securities | ​ | $ | 884,482 | ​ | $ | 5 | ​ | $ | (139,134) | ​ | $ | 213 | ​ | $ | 745,353
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2022
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Allowance for | ​ | Fair
(dollars in thousands) |  | Cost | ​ | Gains | ​ | Losses | ​ | Credit Losses |  | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury and agencies | ​ | $ | 3,518 | ​ | $ | 19 | ​ | $ | (17) | ​ | ​ | N/A | ​ | $ | 3,520
Mortgage backed securities | ​ |  |  | ​ |  | ​ | ​ |  | ​ | ​ | ​ | ​ | ​ |  |
Residential agency | ​ |  | 705,845 | ​ |  | 2 | ​ |  | (118,168) | ​ | ​ | N/A | ​ |  | 587,679
Commercial | ​ |  | 70,669 | ​ |  | — | ​ |  | (7,111) | ​ | ​ | N/A | ​ |  | 63,558
Asset backed securities | ​ |  | 34 | ​ |  | — | ​ |  | — | ​ | ​ | N/A | ​ |  | 34
Corporate bonds | ​ |  | 69,501 | ​ |  | — | ​ |  | (6,968) | ​ | ​ | N/A | ​ |  | 62,533
Total available-for-sale investment securities | ​ | ​ | 849,567 | ​ | ​ | 21 | ​ | ​ | (132,264) | ​ | ​ | N/A | ​ | ​ | 717,324
Held-to-maturity | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Obligations of state and political agencies | ​ | ​ | 137,787 | ​ |  | — | ​ |  | (17,736) | ​ | ​ | N/A | ​ | ​ | 120,051
Mortgage backed securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Residential agency | ​ | ​ | 184,115 | ​ |  | — | ​ |  | (33,254) | ​ | ​ | N/A | ​ | ​ | 150,861
Total held-to-maturity investment securities | ​ | ​ | 321,902 | ​ | ​ | — | ​ | ​ | (50,990) | ​ | ​ | N/A | ​ | ​ | 270,912
Total investment securities | ​ | $ | 1,171,469 | ​ | $ | 21 | ​ | $ | (183,254) | ​ | ​ | N/A | ​ | $ | 988,236
Schedule of proceeds from the sale of available for sale securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year ended
​ | ​ | December 31,
(dollars in thousands) |  | 2023 |  | 2022 |  | 2021
Proceeds | ​ | $ | 171,758 | ​ | $ | — | ​ | $ | 13,189
Realized gains | ​ |  | — | ​ |  | — | ​ | ​ | 114
Realized losses | ​ |  | (24,643) | ​ |  | — | ​ | ​ | —
Schedule of proceeds from the call of held-to-maturity investment securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year ended
​ | ​ | December 31,
(dollars in thousands) |  | 2023 |  | 2022 |  | 2021
Proceeds | ​ | $ | 242 | ​ | $ | 963 | ​ | $ | 1,772
Realized gains | ​ |  | — | ​ |  | — | ​ | ​ | 11
Realized losses | ​ |  | — | ​ |  | — | ​ | ​ | —
Schedule of investment securities with gross unrealized losses | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | December 31, 2023
​ | ​ | ​ | ​ | Less than 12 Months | ​ | Over 12 Months | ​ | Total
​ | ​ | Number of | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair
(dollars in thousands) |  | Holdings | ​ | Losses |  | Value |  | Losses |  | Value |  | Losses |  | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury and agencies | ​ | 1 | ​ | $ | (3) | ​ | $ | 489 | ​ | $ | — | ​ | $ | — | ​ | $ | (3) | ​ | $ | 489
Mortgage backed securities | ​ | ​ | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |
Residential agency | ​ | 112 | ​ |  | — | ​ |  | 43 | ​ |  | (88,547) | ​ |  | 435,505 | ​ |  | (88,547) | ​ |  | 435,548
Commercial | ​ | 1 | ​ |  | — | ​ |  | — | ​ |  | (123) | ​ |  | 1,353 | ​ |  | (123) | ​ |  | 1,353
Asset backed securities | ​ | 3 | ​ |  | — | ​ |  | — | ​ |  | (1) | ​ |  | 25 | ​ |  | (1) | ​ |  | 25
Corporate bonds | ​ | 12 | ​ |  | — | ​ |  | — | ​ |  | (9,349) | ​ |  | 48,644 | ​ |  | (9,349) | ​ |  | 48,644
Total available-for-sale investment securities | ​ | 129 | ​ | $ | (3) | ​ | $ | 532 | ​ | $ | (98,020) | ​ | $ | 485,527 | ​ | $ | (98,023) | ​ | $ | 486,059
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | ​ | ​ | December 31, 2022
​ | ​ | ​ | ​ | Less than 12 Months | ​ | Over 12 Months | ​ | Total
​ | ​ | Number of | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair
(dollars in thousands) |  | Holdings | ​ | Losses |  | Value |  | Losses |  | Value |  | Losses |  | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury and agencies | ​ | 1 | ​ | $ | (17) | ​ | $ | 509 | ​ | $ | — | ​ | $ | — | ​ | $ | (17) | ​ | $ | 509
Mortgage backed securities | ​ | ​ | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |
Residential agency | ​ | 145 | ​ |  | (10,457) | ​ |  | 79,693 | ​ |  | (107,711) | ​ |  | 507,418 | ​ |  | (118,168) | ​ |  | 587,111
Commercial | ​ | 17 | ​ |  | (4,835) | ​ |  | 50,437 | ​ |  | (2,276) | ​ |  | 13,120 | ​ |  | (7,111) | ​ |  | 63,557
Asset backed securities | ​ | 3 | ​ |  | — | ​ |  | 32 | ​ |  | — | ​ |  | 2 | ​ |  | — | ​ |  | 34
Corporate bonds | ​ | 17 | ​ |  | (4,452) | ​ |  | 48,048 | ​ |  | (2,516) | ​ |  | 14,484 | ​ |  | (6,968) | ​ |  | 62,532
Total available-for-sale investment securities | ​ | 183 | ​ | ​ | (19,761) | ​ | ​ | 178,719 | ​ | ​ | (112,503) | ​ | ​ | 535,024 | ​ | ​ | (132,264) | ​ | ​ | 713,743
Held-to-maturity | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Obligations of state and political agencies | ​ | 181 | ​ | ​ | (3,336) | ​ | ​ | 18,788 | ​ | ​ | (14,400) | ​ | ​ | 98,762 | ​ | ​ | (17,736) | ​ | ​ | 117,550
Mortgage backed securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Residential agency | ​ | 27 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | (33,254) | ​ | ​ | 150,861 | ​ | ​ | (33,254) | ​ | ​ | 150,861
Total held-to-maturity investment securities | ​ | 208 | ​ | ​ | (3,336) | ​ | ​ | 18,788 | ​ | ​ | (47,654) | ​ | ​ | 249,623 | ​ | ​ | (50,990) | ​ | ​ | 268,411
Total investment securities | ​ | 391 | ​ | $ | (23,097) | ​ | $ | 197,507 | ​ | $ | (160,157) | ​ | $ | 784,647 | ​ | $ | (183,254) | ​ | $ | 982,154
Schedule of contractual maturity of amortized cost and estimated fair value | ​ The following table presents amortized cost and fair value of AFS investment securities and the carrying value and fair value of HTM investment securities at December 31, 2023, by contractual maturity:
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Held-to-maturity | ​ | Available-for-sale
​ | ​ | Carrying | ​ | Fair | ​ | Amortized | ​ | Fair
(dollars in thousands) |  | Value | ​ | Value | ​ | Cost |  | Value
Due within one year or less | ​ | $ | 8,588 | ​ | $ | 8,474 | ​ | $ | — | ​ | $ | —
Due after one year through five years | ​ |  | 47,995 | ​ |  | 44,557 | ​ |  | 524 | ​ |  | 521
Due after five years through ten years | ​ |  | 60,289 | ​ |  | 52,729 | ​ |  | 59,477 | ​ |  | 50,004
Due after 10 years | ​ |  | 12,731 | ​ |  | 11,230 | ​ |  | 613 | ​ |  | 617
​ | ​ | ​ | 129,603 | ​ | ​ | 116,990 | ​ | ​ | 60,614 | ​ | ​ | 51,142
Mortgage-backed securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Residential agency | ​ | ​ | 170,125 | ​ | ​ | 141,627 | ​ | ​ | 524,140 | ​ | ​ | 435,594
Total investment securities | ​ | $ | 299,728 | ​ | $ | 258,617 | ​ | $ | 584,754 | ​ | $ | 486,736
​
Schedule of federal home loan bank | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, | ​ | December 31,
(dollars in thousands) |  | 2023 |  | 2022
Federal Reserve | ​ | $ | 4,623 | ​ | $ | 4,595
FHLB | ​ |  | 16,566 | ​ |  | 19,362

X
- Definition Tabular disclosure of the proceeds from sales or calls of held-to-maturity securities and the gross realized gains and gross realized losses that have been included in earnings as a result of those sales. + References No definition available. + Details
Name: | alrs_ScheduleOfRealizedGainLossOfHeldToMaturitySecuritiesTableTextBlock
Namespace Prefix: | alrs_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- 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 -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-9 Reference 2: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-3 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 Reference 4: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 Reference 5: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 Reference 6: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (aa) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 Reference 7: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (aaa) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 Reference 8: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 2 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-2 Reference 9: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-3 Reference 10: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-3 Reference 11: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (c) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-3 Reference 12: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 3 -Subparagraph (d) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-3 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

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), in unrealized loss position, without allowance for credit loss. Includes beneficial interest in securitized financial asset. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 55 -Paragraph 8 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479081/326-30-55-8 Reference 2: http://fasb.org/us-gaap/role/ref/otherTransitionRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-6 Reference 3: http://www.xbrl.org/2009/role/commonPracticeRef -Topic 326 -SubTopic 30 -Name Accounting Standards Codification -Section 50 -Paragraph 4 -Publisher FASB -URI https://asc.fasb.org//1943274/2147479106/326-30-50-4 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPositionFairValueTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of advances made and reported by Federal Home Loan Bank (FHLBank). + References No definition available. + Details
Name: | us-gaap_FederalHomeLoanBankAdvancesTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of maturities of an entity's investments as well as any other information pertinent to the investments. + References No definition available. + Details
Name: | us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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://www.xbrl.org/2009/role/commonPracticeRef -Topic 320 -SubTopic 10 -Name Accounting Standards Codification -Section 50 -Paragraph 9 -Subparagraph (a) -Publisher FASB -URI https://asc.fasb.org//1943274/2147481800/320-10-50-9 + Details
Name: | us-gaap_ScheduleOfRealizedGainLossTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration