Leases - Supplemental cash flow information related to leases (Details) $ in Thousands	12 Months Ended
Dec. 31, 2022 USD ($)
Cash Paid For Amounts Included In The Measurement Of Lease Liabilities Abstract
Operating cash flows	$ 3,145
Right Of Use Assets Obtained In Exchange For New Lease Liabilities Abstract
Capitalized operating leases	$ 982

Cash paid for amounts included in the measurement of lease liabilities and capitalized operating leases.

No definition available.

Name:	dh_CashPaidForAmountsIncludedInTheMeasurementOfLeaseLiabilitiesAbstract
Namespace Prefix:	dh_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Right Of Use Assets Obtained In Exchange For New Lease Liabilities Abstract

+ References

No definition available.

+ Details

Name:	dh_RightOfUseAssetsObtainedInExchangeForNewLeaseLiabilitiesAbstract
Namespace Prefix:	dh_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 45
-Paragraph 5
-Subparagraph (c)
-URI https://asc.fasb.org/extlink&oid=123391704&loc=SL77918643-209977

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (g)(1)
-URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918686-209980

+ Details

Name:	us-gaap_OperatingLeasePayments
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of increase in right-of-use asset obtained in exchange for operating lease liability.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 55
-Paragraph 53
-URI https://asc.fasb.org/extlink&oid=123414884&loc=SL77918982-209971

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (g)(2)
-URI https://asc.fasb.org/extlink&oid=128292326&loc=SL77918686-209980

+ Details

Name:	us-gaap_RightOfUseAssetObtainedInExchangeForOperatingLeaseLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration