XML 39 R28.htm IDEA: XBRL DOCUMENT
v3.21.2

Investment Securities (Tables) | 9 Months Ended
--- | ---
Sep. 30, 2021
Investment Securities |
Schedule of amortized cost of investment securities to estimated fair values | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | September 30, 2021
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
(dollars in thousands) |  | Cost | ​ | Gains | ​ | Losses |  | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury and agencies | ​ | $ | 5,382 | ​ | $ | 87 | ​ | $ | — | ​ | $ | 5,469
Mortgage backed securities | ​ |  |  | ​ |  | ​ | ​ |  | ​ | ​ |  | ​
Residential agency | ​ |  | 523,743 | ​ |  | 2,219 | ​ |  | (7,490) | ​ |  | 518,472
Commercial | ​ |  | 91,336 | ​ |  | 3,582 | ​ |  | — | ​ |  | 94,918
Asset backed securities | ​ |  | 61 | ​ |  | 3 | ​ |  | — | ​ |  | 64
Corporate bonds | ​ |  | 35,038 | ​ |  | 1,321 | ​ |  | — | ​ |  | 36,359
Total available-for-sale investment securities | ​ | ​ | 655,560 | ​ | ​ | 7,212 | ​ | ​ | (7,490) | ​ | ​ | 655,282
Held-to-maturity | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Obligations of state and political agencies | ​ | ​ | 145,172 | ​ |  | 1,530 | ​ |  | (29) | ​ |  | 146,673
Mortgage backed securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Residential agency | ​ | ​ | 217,414 | ​ |  | 55 | ​ |  | (602) | ​ |  | 216,867
Total held-to-maturity investment securities | ​ | ​ | 362,586 | ​ | ​ | 1,585 | ​ | ​ | (631) | ​ | ​ | 363,540
Total investment securities | ​ | $ | 1,018,146 | ​ | $ | 8,797 | ​ | $ | (8,121) | ​ | $ | 1,018,822
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2020
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
(dollars in thousands) |  | Cost | ​ | Gains | ​ | Losses |  | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
U.S. Treasury and agencies | ​ | $ | 5,926 | ​ | $ | — | ​ | $ | (19) | ​ | $ | 5,907
Obligations of state and political agencies | ​ |  | 148,491 | ​ |  | 5,282 | ​ |  | — | ​ |  | 153,773
Mortgage backed securities | ​ |  |  | ​ |  | ​ | ​ |  | ​ | ​ |  |
Residential agency | ​ |  | 303,760 | ​ |  | 3,395 | ​ |  | (436) | ​ |  | 306,719
Commercial | ​ |  | 89,300 | ​ |  | 5,678 | ​ |  | — | ​ |  | 94,978
Asset backed securities | ​ |  | 109 | ​ |  | 6 | ​ |  | — | ​ |  | 115
Corporate bonds | ​ |  | 30,552 | ​ |  | 388 | ​ |  | (90) | ​ |  | 30,850
Total available-for-sale investment securities | ​ | $ | 578,138 | ​ | $ | 14,749 | ​ | $ | (545) | ​ | $ | 592,342
Schedule of investment securities with gross unrealized losses | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | September 30, 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 | ​ |  | (7,416) | ​ |  | 340,254 | ​ |  | (74) | ​ |  | 9,057 | ​ |  | (7,490) | ​ |  | 349,311
Commercial | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | —
Asset backed securities | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | 2 | ​ |  | — | ​ |  | 2
Corporate bonds | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | —
Total available-for-sale investment securities | ​ | ​ | (7,416) | ​ | ​ | 340,254 | ​ | ​ | (74) | ​ | ​ | 9,059 | ​ | ​ | (7,490) | ​ | ​ | 349,313
Held-to-maturity | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Obligations of state and political agencies | ​ | ​ | (29) | ​ | ​ | 22,550 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | (29) | ​ | ​ | 22,550
Mortgage backed securities | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Residential agency | ​ | ​ | (602) | ​ | ​ | 80,145 | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | (602) | ​ | ​ | 80,145
Total held-to-maturity investment securities | ​ | ​ | (631) | ​ | ​ | 102,695 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | (631) | ​ | ​ | 102,695
Total investment securities | ​ | $ | (8,047) | ​ | $ | 442,949 | ​ | ​ | (74) | ​ | ​ | 9,059 | ​ | ​ | (8,121) | ​ | ​ | 452,008
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2020
​ | ​ | 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 | ​ | $ | (10) | ​ | $ | 4,509 | ​ | $ | (9) | ​ | $ | 1,309 | ​ | $ | (19) | ​ | $ | 5,818
Obligations of state and political agencies | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | —
Mortgage backed securities | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |
Residential agency | ​ |  | (432) | ​ |  | 68,494 | ​ |  | (4) | ​ |  | 2,356 | ​ |  | (436) | ​ |  | 70,850
Commercial | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | —
Asset backed securities | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | 2 | ​ |  | — | ​ |  | 2
Corporate bonds | ​ |  | (90) | ​ |  | 16,454 | ​ |  | — | ​ |  | — | ​ |  | (90) | ​ |  | 16,454
Total available-for-sale investment securities | ​ | $ | (532) | ​ | $ | 89,457 | ​ | $ | (13) | ​ | $ | 3,667 | ​ | $ | (545) | ​ | $ | 93,124
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 | ​ | $ | 4,690 | ​ | $ | 4,690 | ​ | $ | — | ​ | $ | —
Due after one year through five years | ​ |  | 34,282 | ​ |  | 34,359 | ​ |  | 3,270 | ​ |  | 3,376
Due after five years through ten years | ​ |  | 75,197 | ​ |  | 76,120 | ​ |  | 83,891 | ​ |  | 87,330
Due after 10 years | ​ |  | 248,417 | ​ |  | 248,371 | ​ |  | 568,399 | ​ |  | 564,576
Total investment securities | ​ | $ | 362,586 | ​ | $ | 363,540 | ​ | $ | 655,560 | ​ | $ | 655,282
Schedule of proceeds from the sale of available for sale securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Three months ended | ​ | Nine months ended
​ | ​ | September 30, | ​ | September 30,
(dollars in thousands) |  | 2021 |  | 2020 |  | 2021 |  | 2020
Proceeds | ​ | $ | — | ​ | $ | 35,125 | ​ | $ | 13,189 | ​ | $ | 74,630
Realized gains | ​ |  | — | ​ |  | 1,428 | ​ |  | 114 | ​ |  | 2,722
Realized losses | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | —
Schedule of proceeds from the sale of held-to-maturity investment securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Three months ended | ​ | Nine months ended
​ | ​ | September 30, | ​ | September 30,
(dollars in thousands) |  | 2021 |  | 2020 |  | 2021 |  | 2020
Proceeds | ​ | $ | 348 | ​ | $ | — | ​ | $ | 1,763 | ​ | $ | —
Realized gains | ​ |  | 11 | ​ |  | — | ​ |  | 11 | ​ |  | —
Realized losses | ​ |  | — | ​ |  | — | ​ |  | — | ​ |  | —
Schedule of federal home loan bank | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | September 30, | ​ | December 31,
(dollars in thousands) |  | 2021 |  | 2020
Federal Reserve | ​ | $ | 2,675 | ​ | $ | 2,675
FHLB | ​ |  | 3,827 | ​ |  | 3,090

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
Name: | alrs_DebtSecuritiesAvailableForSaleAndHeldToMaturityUnrealizedLossPositionFairValueTableTextBlock
Namespace Prefix: | alrs_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the proceeds from sales 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: | nonnum: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 -Publisher FASB -Name Accounting Standards Codification -Topic 320 -URI http://asc.fasb.org/topic&trid=2196928 + Details
Name: | us-gaap_DebtSecuritiesAvailableForSaleTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum: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: | nonnum: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: | nonnum: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://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=121645371&loc=d3e27357-111563 + Details
Name: | us-gaap_ScheduleOfRealizedGainLossTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration