XML 39 R28.htm IDEA: XBRL DOCUMENT
v3.5.0.2

Significant Accounting Policies - Narrative (Detail) | 3 Months Ended | 6 Months Ended | 12 Months Ended
--- | --- | --- | ---
Jun. 30, 2016 USD ($) | Jun. 30, 2015 USD ($) | Jun. 30, 2016 USD ($) Segment | Jun. 30, 2015 USD ($) | Dec. 31, 2015 USD ($)
Business Organization And Significant Accounting Policies [Line Items] |  |  |  |  |
Cumulative-effect adjustment from the adoption of ASU 2015-02 (Note 2) |  |  | $ 4,031,756 | $ 0 |
Number of business segment | Segment |  |  | 1 |  |
Allowance for doubtful accounts | $ 0 |  | $ 0 |  | $ 0
Accounts Receivable, Related Parties | 9,200,000 |  | 9,200,000 |  | 9,200,000
Transfers between fair value levels | 0 |  | $ 0 |  | 0
Client Performance Period |  |  | 5 years |  |
Advance commissions amortization period |  |  | 12 months |  |
Liability for Uncertain Tax Positions, Current | 0 |  | $ 0 |  | $ 0
Alternative Investments, Fair Value Disclosure | 1,400,000 |  | 1,400,000 |  |
Level 1 Inputs |  |  |  |  |
Business Organization And Significant Accounting Policies [Line Items] |  |  |  |  |
Value of Investment | 102,624,785 |  | 102,624,785 |  |
Mutual Funds | Money Market Funds | Level 1 Inputs |  |  |  |  |
Business Organization And Significant Accounting Policies [Line Items] |  |  |  |  |
Cash Equivalent Fair Value | 46,000,000 |  | 46,000,000 |  |
Incentive Fees Method One [Member] |  |  |  |  |
Business Organization And Significant Accounting Policies [Line Items] |  |  |  |  |
Performance Incentive Fees |  |  | 0 | 0 |
Investment Advisory Services [Member] |  |  |  |  |
Business Organization And Significant Accounting Policies [Line Items] |  |  |  |  |
Revenue from Related Parties | 22,000,000 | $ 20,000,000 | 42,300,000 | 38,500,000 |
Mutual fund administrative services [Member] |  |  |  |  |
Business Organization And Significant Accounting Policies [Line Items] |  |  |  |  |
Revenue from Related Parties | $ 3,000,000 | $ 3,500,000 | $ 5,800,000 | $ 6,600,000 |
Class A [Member] |  |  |  |  |
Business Organization And Significant Accounting Policies [Line Items] |  |  |  |  |
Rate of Administrative Service Fees |  |  | 0.24% |  | 0.24%
Class C [Member] |  |  |  |  |
Business Organization And Significant Accounting Policies [Line Items] |  |  |  |  |
Rate of Administrative Service Fees |  |  | 0.24% |  | 0.24%
Class Y [Member] |  |  |  |  |
Business Organization And Significant Accounting Policies [Line Items] |  |  |  |  |
Rate of Administrative Service Fees |  |  | 0.10% |  | 0.10%

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 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 Value of investment. + References No definition available. + Details
Name: | dhil_ValueOfInvestment
Namespace Prefix: | dhil_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition For an unclassified balance sheet, amount of receivables arising from transactions with related parties. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08(k)(1)) -URI http://asc.fasb.org/extlink&oid=26873400&loc=d3e23780-122690 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 4 -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39622-107864 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(a)(3)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39603-107864 Reference 6: 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(3)(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_AccountsReceivableRelatedParties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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=66008989&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 Fair value of investments in certain entities that calculate net asset value per share, including, but not limited to, by unit, membership interest, or other ownership interest. Investments include, but are not limited to, investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 6A -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=66048111&loc=SL6742756-110258 + Details
Name: | us-gaap_AlternativeInvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount recognized for uncertainty in income taxes classified as current. + 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 Represents the quantification of the effect of adopting the new accounting standard or change in accounting principle expected by the entity to have a significant effect on the entity's financial statements. + References No definition available. + Details
Name: | us-gaap_NewAccountingPronouncementOrChangeInAccountingPrincipleEffectOfAdoptionQuantification
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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
- Definition Amount of revenue, fees and commissions earned from transactions between (a) a parent company and its subsidiaries; (b) subsidiaries of a common parent; (c) an entity and trusts for the benefit of employees, for example, but not limited to, pension and profit-sharing trusts that are managed by or under the trusteeship of the entity's management; (d) an entity and its principal, owners, management, or members of their immediate families; and (e) affiliates. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 225 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SX 210.5-03.1(e)) -URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Related Parties -URI http://asc.fasb.org/extlink&oid=16382449 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 946 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.6-07.1(c)) -URI http://asc.fasb.org/extlink&oid=6488393&loc=d3e606610-122999 + Details
Name: | us-gaap_RevenueFromRelatedParties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
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_IncomeStatementLocationAxis=dhil_IncentiveFeesMethodOneMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=dhil_InvestmentAdvisoryServicesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RelatedPartyTransactionAxis=dhil_MutualfundadministrativeservicesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

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

X
- Details
Name: | us-gaap_PrincipleTransactionRevenueDescriptionOfReportingCategoryAxis=dhil_ClassCMember
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: |