XML 27 R22.htm IDEA: XBRL DOCUMENT
v3.2.0.727

Significant Accounting Policies - Assets under Management (AUM) Subject to Incentive Fees and Incentive Fees (Detail) - USD ($) | 6 Months Ended
--- | ---
Jun. 30, 2015 | Jun. 30, 2014
Principal Transaction Revenue [Line Items] |  |
AUM Subject to Incentive Fees | $ 576,430,237 | $ 498,891,932
Incentive Fees Under Method 2 |  |
Principal Transaction Revenue [Line Items] |  |
Performance Incentive Fees | 4,208,180 | 3,614,204
Incentive Fees Under Method 2 | Quarter Ended June 30, 2017 |  |
Principal Transaction Revenue [Line Items] |  |
Performance Incentive Fees | 3,655,964 | 3,614,204
Incentive Fees Under Method 2 | Quarter Ended December 31, 2018 |  |
Principal Transaction Revenue [Line Items] |  |
Performance Incentive Fees | 265,040 | 0
Incentive Fees Under Method 2 | Quarter Ended September 30, 2019 |  |
Principal Transaction Revenue [Line Items] |  |
Performance Incentive Fees | 278,658 | 0
Incentive Fees Under Method 2 | Quarter Ended March 31, 2020 |  |
Principal Transaction Revenue [Line Items] |  |
Performance Incentive Fees | $ 8,518 | $ 0

X
- Definition Assets under management (AUM) subject to incentive fees and incentive fees. + References No definition available. + Details
Name: | dhil_AssetsUnderManagementIncentiveFees
Namespace Prefix: | dhil_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of revenue earned by the entity based on the investment results achieved. Excludes fees based upon a percentage of the assets under management not performance-related. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.13 (a)) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 + Details
Name: | us-gaap_PerformanceFees
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_PrincipleTransactionRevenueLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_IncomeStatementLocationAxis=dhil_IncentiveFeesMethodTwoMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis=dhil_AssetUnderManagementContractualPeriodEndDateMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis=dhil_AssetUnderManagementContractualPeriodEndDate2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis=dhil_AssetUnderManagementContractualPeriodEndDate3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis=dhil_AssetUnderManagementContractualPeriodEndDate4Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |