XML 15 R25.htm IDEA: XBRL DOCUMENT v3.3.0.814

Significant Accounting Policies - Narrative (Detail)	3 Months Ended		6 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2015	Sep. 30, 2015 USD ($) Segment	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Business Organization And Significant Accounting Policies [Line Items]
Number of business segment | Segment				1
Allowance for doubtful accounts	$ 0			$ 0		$ 0
Transfers between fair value levels	0			$ 0		0
Client Performance Period				5 years
Advance commissions amortization period				12 months
Contractual Expense Reimburse, Net	711,053	$ 441,411		$ 1,925,557	$ 1,238,765
Liability for Uncertain Tax Positions, Current	$ 0			$ 0		$ 0
Class A and Class C [Member]
Business Organization And Significant Accounting Policies [Line Items]
Rate of Administrative Service Fees				0.24%
Class A, C, and I Shares
Business Organization And Significant Accounting Policies [Line Items]
Rate of Administrative Service Fees						0.25%
Class I
Business Organization And Significant Accounting Policies [Line Items]
Rate of Administrative Service Fees	0.21%		0.24%
Class Y
Business Organization And Significant Accounting Policies [Line Items]
Rate of Administrative Service Fees				0.10%		0.10%
Mutual Funds | Money Market Funds | Level 1 Inputs
Business Organization And Significant Accounting Policies [Line Items]
Cash Equivalent Fair Value	$ 50,100,000			$ 50,100,000		$ 31,800,000
Incentive Fees Method One [Member]
Business Organization And Significant Accounting Policies [Line Items]
Performance Incentive Fees				$ 0	$ 0

X

- Definition

Advance commissions amortization period.

+ References

No definition available.

+ Details

Name:	dhil_AdvanceCommissionsAmortizationPeriod
Namespace Prefix:	dhil_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Business Organization And Significant Accounting Policies [Line Items]

+ References

No definition available.

+ Details

Name:	dhil_BusinessOrganizationAndSignificantAccountingPoliciesLineItems
Namespace Prefix:	dhil_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Cash equivalent fair value.

+ References

No definition available.

+ Details

Name:	dhil_CashEquivalentFairValue
Namespace Prefix:	dhil_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Contractual Expense Reimbursement netted against applicable expenses under agreement

+ References

No definition available.

+ Details

Name:	dhil_ContractualExpenseReimburseNet
Namespace Prefix:	dhil_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

X

- Definition

Fair Value, Transfers Between Level 1, Level 2, or Level 3, Amount

+ References

No definition available.

+ Details

Name:	dhil_FairValueTransfersBetweenLevel1Level2orLevel3Amount
Namespace Prefix:	dhil_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Definition

Rate of administrative service fees.

+ References

No definition available.

+ Details

Name:	dhil_RateOfAdministrativeServiceFees
Namespace Prefix:	dhil_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Rolling Client Investment Performance Period

+ References

No definition available.

+ Details

Name:	dhil_RollingClientInvestmentPerformancePeriod
Namespace Prefix:	dhil_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

X

- Definition

For an unclassified balance sheet, a valuation allowance for receivables due a company that are expected to be uncollectible.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 310



-SubTopic 10



-Section 50



-Paragraph 4



-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5074-111524



Reference 2: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 210



-SubTopic 10



-Section S99



-Paragraph 1



-Subparagraph (SX 210.5-02.4)



-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AllowanceForDoubtfulAccountsReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

The current portion of the amount recognized for uncertain tax positions as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef



-Publisher FASB



-Name Accounting Standards Codification



-Topic 210



-SubTopic 10



-Section S99



-Paragraph 1



-Subparagraph (SX 210.5-02.20)



-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_LiabilityForUncertainTaxPositionsCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

X

- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfOperatingSegments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

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

- Details

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

X

- Details

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

X

- Details

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

X

- Details

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

X

- Details

Name:	invest_InvestmentIssuerAxis=dhil_MutualFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_MoneyMarketFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

X

- Details

Name:	us-gaap_IncomeStatementLocationAxis=dhil_IncentiveFeesMethodOneMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: