XML 51 R40.htm IDEA: XBRL DOCUMENT v3.19.1

Operating Leases - Narrative (Detail) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2019 USD ($) ft² location	Dec. 31, 2018 USD ($)	Jan. 01, 2019 USD ($)
Area of operating lease | ft²	37,829
Number of office space locations | location	1
Operating lease, right-of-use asset	$ 2.8
Operating lease, liability	$ 3.5
Operating lease expense excluding rent		$ 0.4
Accounting Standards Update 2016-02
Operating lease, right-of-use asset			$ 2.9
Operating lease, liability			$ 3.6

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

Lessee Leasing Agreements, Operating Leases, locations

+ References

No definition available.

+ Details

Name:	dhil_LesseeLeasingAgreementsOperatingLeaseslocations
Namespace Prefix:	dhil_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

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

- Definition

Present value of lessee's discounted obligation for lease payments from operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

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

X

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=77888419&loc=SL77918627-209977

+ Details

Name:	us-gaap_OperatingLeaseRightOfUseAsset
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

X

- Details

Name:	us-gaap_AdjustmentsForNewAccountingPronouncementsAxis=us-gaap_AccountingStandardsUpdate201602Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: