XML 141 R125.htm IDEA: XBRL DOCUMENT
v3.20.4

REGULATORY CAPITAL REQUIREMENTS (Details) $ in Thousands | Dec. 31, 2020 USD ($) | Dec. 31, 2019 USD ($)
--- | --- | ---
Common equity tier 1 capital to risk weighted assets: |  |
Actual, Ratio (as a percent) | 4.5 | 7.0
Total Capital (to risk weighted assets) |  |
Actual, Ratio (as a percent) | 8.0 | 10.5
Tier 1 Capital (to risk weighted assets) |  |
Actual, Ratio (as a percent) | 6.0 | 8.5
Basel III |  |
Common equity tier 1 capital to risk weighted assets: |  |
Actual, Amount | $ 424,652 | $ 397,800
Actual, Ratio (as a percent) | 10.3 | 10.2
Minimum Capital Adequacy Requirement, Amount | $ 185,479 | $ 176,121
Minimum Capital Adequacy Requirement, Ratio (as a percent) | 4.50% | 4.50%
Minimum Capital Adequacy Requirement with Capital Conservation Buffer, Amount | $ 288,523 | $ 273,967
Minimum Capital Adequacy Requirement with Capital Conservation Buffer (as a percent) | 7.00% | 7.00%
Total Capital (to risk weighted assets) |  |
Actual, Amount | $ 537,664 | $ 510,862
Actual, Ratio (as a percent) | 13.0 | 13.1
Minimum Capital Adequacy Requirement, Amount | $ 329,740 | $ 313,105
Minimum Capital Adequacy Requirement (as a percent) | 8.0 | 8.0
Minimum Capital Adequacy Requirement with Capital Conservation Buffer, Amount | $ 432,784 | $ 410,950
Minimum Capital Adequacy Requirement with Capital Conservation Buffer (as a percent) | 10.50% | 10.50%
Tier 1 Capital (to risk weighted assets) |  |
Actual, Amount | $ 424,652 | $ 397,800
Actual, Ratio (as a percent) | 10.3 | 10.2
For Capital Adequacy Purposes, Amount | $ 247,305 | $ 234,828
For Capital Adequacy Purposes, Ratio (as a percent) | 6.0 | 6.0
Minimum Capital Adequacy Requirement with Capital Conservation Buffer, Amount | $ 350,349 | $ 332,674
Minimum Capital Adequacy Requirement with Capital Conservation Buffer (as a percent) | 8.50% | 8.50%
Tier 1 Capital (to average assets) |  |
Actual, Amount | $ 424,652 | $ 397,800
Actual, Ratio (as a percent) | 6.8 | 8.5
For Capital Adequacy Purposes, Amount | $ 249,502 | $ 187,386
For Capital Adequacy Purposes, Ratio (as a percent) | 4.0 | 4.0
BNB Bank (Bank) | Basel III |  |
Common equity tier 1 capital to risk weighted assets: |  |
Actual, Amount | $ 503,524 | $ 474,056
Actual, Ratio (as a percent) | 12.2 | 12.1
Minimum Capital Adequacy Requirement, Amount | $ 185,465 | $ 176,114
Minimum Capital Adequacy Requirement, Ratio (as a percent) | 4.50% | 4.50%
Minimum Capital Adequacy Requirement with Capital Conservation Buffer, Amount | $ 288,502 | $ 273,954
Minimum Capital Adequacy Requirement with Capital Conservation Buffer (as a percent) | 7.00% | 7.00%
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount | $ 267,895 | $ 254,386
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio (as a percent) | 6.50% | 6.50%
Total Capital (to risk weighted assets) |  |
Actual, Amount | $ 544,536 | $ 507,118
Actual, Ratio (as a percent) | 13.2 | 13.0
Minimum Capital Adequacy Requirement, Amount | $ 329,716 | $ 313,091
Minimum Capital Adequacy Requirement (as a percent) | 8.0 | 8.0
Minimum Capital Adequacy Requirement with Capital Conservation Buffer, Amount | $ 432,753 | $ 410,932
Minimum Capital Adequacy Requirement with Capital Conservation Buffer (as a percent) | 10.50% | 10.50%
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount | $ 412,145 | $ 391,363
Minimum To Be Well Capitalized Under Prompt Corrective Action Provisions (as a percent) | 10.0 | 10.0
Tier 1 Capital (to risk weighted assets) |  |
Actual, Amount | $ 503,524 | $ 474,056
Actual, Ratio (as a percent) | 12.2 | 12.1
For Capital Adequacy Purposes, Amount | $ 247,287 | $ 234,818
For Capital Adequacy Purposes, Ratio (as a percent) | 6.0 | 6.0
Minimum Capital Adequacy Requirement with Capital Conservation Buffer, Amount | $ 350,324 | $ 332,659
Minimum Capital Adequacy Requirement with Capital Conservation Buffer (as a percent) | 8.50% | 8.50%
To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount | $ 329,716 | $ 313,091
To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio (as a percent) | 8.0 | 8.0
Tier 1 Capital (to average assets) |  |
Actual, Amount | $ 503,524 | $ 474,056
Actual, Ratio (as a percent) | 8.1 | 10.1
For Capital Adequacy Purposes, Amount | $ 249,389 | $ 187,377
For Capital Adequacy Purposes, Ratio (as a percent) | 4.0 | 4.0
To Be Well Capitalized Under Prompt Corrective Action Provisions, Amount | $ 311,737 | $ 234,222
To Be Well Capitalized Under Prompt Corrective Action Provisions, Ratio (as a percent) | 5.0 | 5.0

X
- Definition The Minimum amount of Minimum Capital Adequacy Requirement with Capital Conservation Buffer under the regulatory framework for prompt corrective action. + References No definition available. + Details
Name: | dcom_CapitalRequiredForMinimumCapitalAdequacyRequirement
Namespace Prefix: | dcom_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The Minimum amount of Minimum Capital Adequacy Requirement with Capital Conservation Buffer under the regulatory framework for prompt corrective action. + References No definition available. + Details
Name: | dcom_CapitalRequiredForMinimumCapitalAdequacyRequirementToRiskWeightedAssets
Namespace Prefix: | dcom_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the minimum amount of common equity Tier 1 Risk Based Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References No definition available. + Details
Name: | dcom_CommonEquityTierOneCapitalRequiredForMinimumCapitalAdequacyRequirementWithCapitalConservationBuffer
Namespace Prefix: | dcom_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Represents the minimum common equity Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References No definition available. + Details
Name: | dcom_CommonEquityTierOneCapitalRequiredForMinimumCapitalAdequacyRequirementWithCapitalConservationBufferToRiskWeightedAssets
Namespace Prefix: | dcom_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the minimum common equity Tier One Capital Ratio (Tier one capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action. + References No definition available. + Details
Name: | dcom_CommonEquityTierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix: | dcom_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Represents the common equity Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action. + References No definition available. + Details
Name: | dcom_CommonEquityTierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix: | dcom_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition The amount of Tier 1 Risk Based Capital required to be Minimum Capital Adequacy Requirement with Capital Conservation Buffer. + References No definition available. + Details
Name: | dcom_TierOneRiskBasedCapitalRequiredForCapitalConservationBuffer
Namespace Prefix: | dcom_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The Tier 1 capital ratio (Tier 1 capital divided by risk weighted assets) required to be Minimum Capital Adequacy Requirement with Capital Conservation Buffer under the regulatory framework for prompt corrective action. + References No definition available. + Details
Name: | dcom_TierOneRiskBasedCapitalRequiredForCapitalConservationBufferToRiskWeightedAssets
Namespace Prefix: | dcom_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of total capital as defined by regulatory framework. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 10 -Section 50 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=6490092&loc=d3e47304-110998 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 948 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=6490092&loc=d3e47080-110998 + Details
Name: | us-gaap_Capital
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition Amount of minimum total risk-based capital required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 + Details
Name: | us-gaap_CapitalRequiredForCapitalAdequacy
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum total risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of minimum total risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CapitalRequiredToBeWellCapitalized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum total risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Ratio of total risk-based capital to risk-weighted assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CapitalToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of Common Equity Tier 1 risk-based capital as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CommonEquityTierOneCapital
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition Ratio of Common Equity Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CommonEquityTierOneCapitalRatio
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of minimum Common Equity Tier 1 risk-based capital required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 + Details
Name: | us-gaap_CommonEquityTierOneCapitalRequiredForCapitalAdequacy
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of minimum Common Equity Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_CommonEquityTierOneCapitalRequiredToBeWellCapitalized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of Tier 1 leverage capital as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapital
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition Amount of minimum Tier 1 leverage capital required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum Tier 1 leverage capital to average assets required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of minimum Tier 1 leverage capital categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum Tier 1 leverage capital to average assets categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Ratio of Tier 1 capital to average assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneLeverageCapitalToAverageAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of Tier 1 risk-based capital as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapital
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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

X
- Definition Amount of minimum Tier 1 risk-based capital required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum Tier 1 risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Amount of minimum Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Ratio of minimum Tier 1 risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Definition Ratio of Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework. + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 505 -Section 50 -Paragraph 1 -Subparagraph (c)(1) -URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826 + Details
Name: | us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets
Namespace Prefix: | us-gaap_
Data Type: | xbrli:pureItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_RegulatoryAgencyAxis=dcom_BaselIiiMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_ConsolidatedEntitiesAxis=dcom_BnbBankMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |