    <SEC-DOCUMENT>0000909108-23-000056-index.html : 20231003
    <SEC-HEADER>0000909108-23-000056.hdr.sgml : 20231003
    <ACCEPTANCE-DATETIME>20231003160252
    ACCESSION NUMBER:		0000909108-23-000056
    CONFORMED SUBMISSION TYPE:	8-K
    PUBLIC DOCUMENT COUNT:		13
    CONFORMED PERIOD OF REPORT:	20231003
    ITEM INFORMATION:		Other Events
    FILED AS OF DATE:		20231003
    DATE AS OF CHANGE:		20231003

    FILER:

    	COMPANY DATA:
    		COMPANY CONFORMED NAME:			DIAMOND HILL INVESTMENT GROUP INC
    		CENTRAL INDEX KEY:			0000909108
    		STANDARD INDUSTRIAL CLASSIFICATION:	INVESTMENT ADVICE [6282]
    		IRS NUMBER:				650190407
    		STATE OF INCORPORATION:			OH
    		FISCAL YEAR END:			1231

    	FILING VALUES:
    		FORM TYPE:		8-K
    		SEC ACT:		1934 Act
    		SEC FILE NUMBER:	000-24498
    		FILM NUMBER:		231303419

    	BUSINESS ADDRESS:
    		STREET 1:		325 JOHN H MCCONNELL BLVD
    		STREET 2:		SUITE 200
    		CITY:			COLUMBUS
    		STATE:			OH
    		ZIP:			43215
    		BUSINESS PHONE:		6142553333

    	MAIL ADDRESS:
    		STREET 1:		325 JOHN H MCCONNELL BLVD
    		STREET 2:		SUITE 200
    		CITY:			COLUMBUS
    		STATE:			OH
    		ZIP:			43215

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	BANC STOCK GROUP INC
    		DATE OF NAME CHANGE:	19971016

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	HEARTLAND GROUP OF COMPANIES INC
    		DATE OF NAME CHANGE:	19940301

    	FORMER COMPANY:
    		FORMER CONFORMED NAME:	HEARTLAND FINANCIAL GROUP INC
    		DATE OF NAME CHANGE:	19930714
    </SEC-HEADER>
    <DOCUMENT>
    <TYPE>8-K
    <SEQUENCE>1
    <FILENAME>dhil-20231003.htm
    <DESCRIPTION>8-K
    <TEXT>
    Document 1 - file: dhil-20231003.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.SCH
    <SEQUENCE>2
    <FILENAME>dhil-20231003.xsd
    <DESCRIPTION>XBRL TAXONOMY EXTENSION SCHEMA DOCUMENT
    <TEXT>
    Document 2 - file: dhil-20231003.xsd

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.LAB
    <SEQUENCE>3
    <FILENAME>dhil-20231003_lab.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION LABEL LINKBASE DOCUMENT
    <TEXT>
    Document 3 - file: dhil-20231003_lab.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EX-101.PRE
    <SEQUENCE>4
    <FILENAME>dhil-20231003_pre.xml
    <DESCRIPTION>XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE DOCUMENT
    <TEXT>
    Document 4 - file: dhil-20231003_pre.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>GRAPHIC
    <SEQUENCE>5
    <FILENAME>dhil-20231003_g1.jpg
    <TEXT>
    Document 5 - file: dhil-20231003_g1.jpg

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>6
    <FILENAME>R1.htm
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 6 - file: R1.htm

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>7
    <FILENAME>dhil-20231003_htm.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 7 - file: dhil-20231003_htm.html

    Document 7 - RAW XML: dhil-20231003_htm.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>EXCEL
    <SEQUENCE>8
    <FILENAME>Financial_Report.xlsx
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 8 - file: Financial_Report.xlsx

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>9
    <FILENAME>Show.js
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 9 - file: Show.js

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>10
    <FILENAME>report.css
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 10 - file: report.css

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>XML
    <SEQUENCE>11
    <FILENAME>FilingSummary.xml
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 11 - file: FilingSummary.html

    Document 11 - RAW XML: FilingSummary.xml

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>JSON
    <SEQUENCE>13
    <FILENAME>MetaLinks.json
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 13 - file: MetaLinks.json

    </DOCUMENT>
    <DOCUMENT>
    <TYPE>ZIP
    <SEQUENCE>14
    <FILENAME>0000909108-23-000056-xbrl.zip
    <DESCRIPTION>IDEA: XBRL DOCUMENT
    <TEXT>
    Document 14 - file: 0000909108-23-000056-xbrl.zip

    </DOCUMENT>
    </SEC-DOCUMENT>