XML 58 R44.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Operating Leases (Details Textual) | 12 Months Ended
--- | ---
Dec. 31, 2016 USD ($) ft² Location | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($)
Leases [Abstract] |  |  |
Lessee Leasing Agreements, Operating Leases, Area under Lease | ft² | 37,829 |  |
Operating Lease Expense Excluding Rent | $ 400,000 | $ 400,000 | $ 400,000
Number of office space locations | Location | 1 |  |
Operating Leases, Future Minimum Payments Due | $ 4,732,865 |  |

X
- Definition Lessee Leasing Agreements, Operating Leases, Area under Lease + References No definition available. + Details
Name: | dhil_LesseeLeasingAgreementsOperatingLeasesAreaunderLease
Namespace Prefix: | dhil_
Data Type: | num:areaItemType
Balance Type: | na
Period Type: | duration

X
- Definition Operating Lease Expense Excluding Rent + References No definition available. + Details
Name: | dhil_OperatingLeaseExpenseExcludingRent
Namespace Prefix: | dhil_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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

X
- Definition Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 10 -Section 55 -Paragraph 40 -Subparagraph (Note 3) -URI http://asc.fasb.org/extlink&oid=6584154&loc=d3e38371-112697 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 840 -SubTopic 20 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6453985&loc=d3e41502-112717 + Details
Name: | us-gaap_OperatingLeasesFutureMinimumPaymentsDue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The number of units (items of property) under operating lease arrangements. + References No definition available. + Details
Name: | us-gaap_PropertySubjectToOrAvailableForOperatingLeaseNumberOfUnits
Namespace Prefix: | us-gaap_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant