XML 60 R37.htm IDEA: XBRL DOCUMENT
v3.22.4

SECURITIES (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2022
SECURITIES |
Major Categories of Securities Owned by Entity | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2022
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
(In thousands) |  | Cost |  | Gains |  | Losses |  | Value
Securities available-for-sale: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Treasury securities | ​ | $ | 246,899 | ​ | $ | — | ​ | $ | (19,643) | ​ | $ | 227,256
Corporate securities | ​ |  | 183,791 | ​ |  | 57 | ​ |  | (17,075) | ​ |  | 166,773
Pass-through mortgage-backed securities ("MBS") issued by government sponsored entities ("GSEs") | ​ |  | 272,774 | ​ |  | — | ​ |  | (31,534) | ​ |  | 241,240
Agency collateralized mortgage obligations ("CMOs") | ​ |  | 331,394 | ​ |  | 2 | ​ |  | (50,057) | ​ |  | 281,339
State and municipal obligations | ​ | ​ | 37,000 | ​ | ​ | — | ​ | ​ | (3,021) | ​ | ​ | 33,979
Total securities available-for-sale | ​ | $ | 1,071,858 | ​ | $ | 59 | ​ | $ | (121,330) | ​ | $ | 950,587
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2022
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrecognized | ​ | Unrecognized | ​ | Fair
(In thousands) |  | Cost |  | Gains |  | Losses |  | Value
Securities held-to-maturity: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Agency notes | ​ | $ | 89,157 | ​ | $ | — | ​ | $ | (14,095) | ​ | $ | 75,062
Corporate securities | ​ | ​ | 9,000 | ​ | ​ | — | ​ | ​ | (553) | ​ | ​ | 8,447
Pass-through MBS issued by GSEs | ​ | ​ | 278,281 | ​ | ​ | — | ​ | ​ | (40,960) | ​ | ​ | 237,321
Agency CMOs | ​ |  | 209,360 | ​ |  | — | ​ |  | (24,431) | ​ |  | 184,929
Total securities held-to-maturity | ​ | $ | 585,798 | ​ | $ | — | ​ | $ | (80,039) | ​ | $ | 505,759
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2021
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrealized | ​ | Unrealized | ​ | Fair
(In thousands) |  | Cost |  | Gains |  | Losses |  | Value
Securities available-for-sale: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Agency notes | ​ | $ | 82,476 | ​ | $ | — | ​ | $ | (2,222) | ​ | $ | 80,254
Treasury securities | ​ | ​ | 247,916 | ​ | ​ | — | ​ | ​ | (3,147) | ​ | ​ | 244,769
Corporate securities | ​ |  | 148,430 | ​ |  | 4,354 | ​ |  | (754) | ​ |  | 152,030
Pass-through MBS issued by GSEs | ​ |  | 528,749 | ​ |  | 4,271 | ​ |  | (6,566) | ​ |  | 526,454
Agency CMOs | ​ |  | 527,348 | ​ |  | 2,705 | ​ |  | (8,795) | ​ |  | 521,258
State and municipal obligations | ​ | ​ | 39,175 | ​ | ​ | 73 | ​ | ​ | (302) | ​ | ​ | 38,946
Total securities available-for-sale | ​ | $ | 1,574,094 | ​ | $ | 11,403 | ​ | $ | (21,786) | ​ | $ | 1,563,711
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2021
​ | ​ | ​ | ​ | ​ | Gross | ​ | Gross | ​ | ​ | ​
​ | ​ | Amortized | ​ | Unrecognized | ​ | Unrecognized | ​ | Fair
(In thousands) |  | Cost |  | Gains |  | Losses |  | Value
Securities held-to-maturity: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Pass-through MBS issued by GSEs | ​ | $ | 118,382 | ​ | $ | 59 | ​ | $ | (1,141) | ​ | $ | 117,300
Agency CMOs | ​ |  | 60,927 | ​ |  | — | ​ |  | (873) | ​ |  | 60,054
Total securities held-to-maturity | ​ | $ | 179,309 | ​ | $ | 59 | ​ | $ | (2,014) | ​ | $ | 177,354
​
Amortized cost and fair value of securities are shown by contractual maturity | ​
​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2022
​ | ​ | Amortized | ​ | Fair
(In thousands) | ​ | Cost | ​ | Value
Available-for-sale | ​ | ​ | ​ | ​ | ​ | ​
Within one year | ​ | $ | 6,355 | ​ | $ | 6,253
One to five years | ​ | ​ | 277,570 | ​ | ​ | 255,798
Five to ten years | ​ | ​ | 178,620 | ​ | ​ | 161,398
Beyond ten years | ​ | ​ | 5,145 | ​ | ​ | 4,559
Pass-through MBS issued by GSEs and agency CMO | ​ | ​ | 604,168 | ​ | ​ | 522,579
Total | ​ | $ | 1,071,858 | ​ | $ | 950,587
​ | ​ | ​ | ​ | ​ | ​ | ​
Held-to-maturity | ​ | ​ | ​ | ​ | ​ | ​
Within one year | ​ | $ | — | ​ | $ | —
One to five years | ​ | ​ | 10,000 | ​ | ​ | 9,314
Five to ten years | ​ | ​ | 88,157 | ​ | ​ | 74,195
Beyond ten years | ​ | ​ | — | ​ | ​ | —
Pass-through MBS issued by GSEs and agency CMO | ​ | ​ | 487,641 | ​ | ​ | 422,250
Total | ​ | $ | 585,798 | ​ | $ | 505,759
​
Summary of Sale of Available-for-sale Securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year Ended December 31,
(In thousands) | ​ | 2022 |  | 2021 |  | 2020
Securities available-for-sale | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
Proceeds | ​ | $ | — | ​ | $ | 138,077 | ​ | $ | 94,252
Gross gains | ​ | ​ | — | ​ | ​ | 1,327 | ​ | ​ | 4,592
Tax expense on gains | ​ | ​ | — | ​ | ​ | 421 | ​ | ​ | 1,444
Gross losses | ​ | ​ | — | ​ | ​ | 120 | ​ | ​ | —
Tax benefit on losses | ​ | ​ | — | ​ | ​ | 38 | ​ | ​ | —
​
Sales of Marketable Equity Securities | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Year Ended December 31,
(In thousands) |  | 2022 |  | 2021 |  | 2020
Proceeds: |  | ​ |  |  | ​ |  |  | ​ |
Marketable equity securities | ​ | $ | — | ​ | $ | 6,101 | ​ | $ | 546
​
Gross Unrealized Losses and Fair Value of Investment Securities by Investment Category and Length of Time in a Continuous Unrealized Loss Position | ​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2022
​ | ​ | Less than 12 | ​ | 12 Consecutive | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Consecutive Months | ​ | Months or Longer | ​ | Total
​ | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized
(In thousands) |  | Value |  | Losses |  | Value |  | Losses |  | Value |  | Losses
Securities available-for-sale: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Treasury securities | ​ | $ | — | ​ | $ | — | ​ | $ | 227,256 | ​ | $ | 19,643 | ​ | $ | 227,256 | ​ | $ | 19,643
Corporate securities | ​ | ​ | 110,707 | ​ | ​ | 8,494 | ​ | ​ | 50,116 | ​ | ​ | 8,581 | ​ | ​ | 160,823 | ​ | ​ | 17,075
Pass-through MBS issued by GSEs | ​ | ​ | 50,813 | ​ | ​ | 2,010 | ​ | ​ | 190,427 | ​ | ​ | 29,524 | ​ | ​ | 241,240 | ​ | ​ | 31,534
Agency CMOs | ​ | ​ | 55,924 | ​ | ​ | 3,454 | ​ | ​ | 220,413 | ​ | ​ | 46,603 | ​ | ​ | 276,337 | ​ | ​ | 50,057
State and municipal obligations | ​ |  | 10,848 | ​ |  | 174 | ​ |  | 22,681 | ​ |  | 2,847 | ​ | ​ | 33,529 | ​ | ​ | 3,021
​
​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | December 31, 2021
​ | ​ | Less than 12 | ​ | 12 Consecutive | ​ | ​ | ​ | ​ | ​ | ​
​ | ​ | Consecutive Months | ​ | Months or Longer | ​ | Total
​ | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized | ​ | Fair | ​ | Unrealized
(In thousands) |  | Value |  | Losses |  | Value |  | Losses |  | Value |  | Losses
Securities available-for-sale: |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |  |  | ​ |
Agency notes | ​ | $ | 58,607 | ​ | $ | 1,369 | ​ | $ | 21,647 | ​ | $ | 853 | ​ | $ | 80,254 | ​ | $ | 2,222
Treasury securities | ​ | ​ | 244,769 | ​ | ​ | 3,147 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | 244,769 | ​ | ​ | 3,147
Corporate securities | ​ | ​ | 37,620 | ​ | ​ | 754 | ​ | ​ | — | ​ | ​ | — | ​ | ​ | 37,620 | ​ | ​ | 754
Pass-through MBS issued by GSEs | ​ | ​ | 422,634 | ​ | ​ | 6,333 | ​ | ​ | 4,748 | ​ | ​ | 233 | ​ | ​ | 427,382 | ​ | ​ | 6,566
Agency CMOs | ​ | ​ | 349,879 | ​ | ​ | 8,672 | ​ | ​ | 3,182 | ​ | ​ | 123 | ​ | ​ | 353,061 | ​ | ​ | 8,795
State and municipal obligations | ​ |  | 18,887 | ​ |  | 302 | ​ |  | — | ​ |  | — | ​ | ​ | 18,887 | ​ | ​ | 302
​

X
- Definition Tabular disclosure of the amortized cost and fair value of securities are shown by contractual maturity. + References No definition available. + Details
Name: | dcom_AmortizedCostAndFairValueOfSecuritiesContractualMaturityTableTextBlock
Namespace Prefix: | dcom_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the sales of available-for-sale securities. + References No definition available. + Details
Name: | dcom_ScheduleOfSalesOfAvailableForSaleAgencySecuritiesTextBlock
Namespace Prefix: | dcom_
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 realized gains and losses on investments reported in the statement of income. + References No definition available. + Details
Name: | us-gaap_RealizedGainLossOnInvestmentsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- 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 https://asc.fasb.org/extlink&oid=126970911&loc=d3e27290-111563 + Details
Name: | us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration