XML 37 R26.htm IDEA: XBRL DOCUMENT v3.19.2

Significant Accounting Policies - Assets under Management (AUM) Subject to Incentive Fees and Incentive Fees (Detail)	6 Months Ended
	Jun. 30, 2019 USD ($)
Quarter Ending September 30, 2019
Principal Transaction Revenue [Line Items]
AUM subject to variable rate fees	$ 38,196,943
Unearned variable rate fees	869,315
Quarter Ending December 31, 2019
Principal Transaction Revenue [Line Items]
AUM subject to variable rate fees	63,035,149
Unearned variable rate fees	578,365
Quarter Ending March 31, 2020
Principal Transaction Revenue [Line Items]
AUM subject to variable rate fees	13,196,879
Unearned variable rate fees	0
Quarter Ending September 30, 2021
Principal Transaction Revenue [Line Items]
AUM subject to variable rate fees	281,012,898
Unearned variable rate fees	5,759,671
Total
Principal Transaction Revenue [Line Items]
AUM subject to variable rate fees	395,441,869
Unearned variable rate fees	$ 7,207,351

X

- Definition

Assets under management (AUM) subject to variable rate fees and variable rate fees.

+ References

No definition available.

+ Details

Name:	dhil_AssetsUnderManagementVariableRateFees
Namespace Prefix:	dhil_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Potential Variable Fees Based Upon Current Investment Results

+ References

No definition available.

+ Details

Name:	dhil_PotentialVariableFeesBasedUponCurrentInvestmentResults
Namespace Prefix:	dhil_
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_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:

X

- Details

Name:	us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis=dhil_AssetUnderManagementContractualPeriodEndTotalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: