<?xml version="1.0" encoding="UTF-8"?>
<informationTable
	xsi:schemaLocation="http://www.sec.gov/edgar/document/thirteenf/informationtable eis_13FDocument.xsd"
	xmlns="http://www.sec.gov/edgar/document/thirteenf/informationtable"
	xmlns:n1="http://www.sec.gov/edgar/document/thirteenf/informationtable"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
	<infoTable>
		<nameOfIssuer>AEMETIS INC</nameOfIssuer>
		<titleOfClass>COM NEW</titleOfClass>
		<cusip>00770K202</cusip>
		<value>20</value>
		<shrsOrPrnAmt>
			<sshPrnamt>25000</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>ANAPLAN INC</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>03272L108</cusip>
		<value>494</value>
		<shrsOrPrnAmt>
			<sshPrnamt>12545</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>ANTERO MIDSTREAM CORP</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>03676B102</cusip>
		<value>5851</value>
		<shrsOrPrnAmt>
			<sshPrnamt>424621</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>ANTERO RES CORP</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>03674X106</cusip>
		<value>59108</value>
		<shrsOrPrnAmt>
			<sshPrnamt>6693966</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>ARAVIVE INC</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>03890D108</cusip>
		<value>1035</value>
		<shrsOrPrnAmt>
			<sshPrnamt>146966</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>BLACK STONE MINERALS L P</nameOfIssuer>
		<titleOfClass>COM UNIT</titleOfClass>
		<cusip>09225M101</cusip>
		<value>1129</value>
		<shrsOrPrnAmt>
			<sshPrnamt>64011</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>CHEVRON CORP NEW</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>166764100</cusip>
		<value>246</value>
		<shrsOrPrnAmt>
			<sshPrnamt>2000</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>DROPBOX INC</nameOfIssuer>
		<titleOfClass>CL A</titleOfClass>
		<cusip>26210C104</cusip>
		<value>2901</value>
		<shrsOrPrnAmt>
			<sshPrnamt>133070</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>EIDOS THERAPEUTICS INC</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>28249H104</cusip>
		<value>6230</value>
		<shrsOrPrnAmt>
			<sshPrnamt>265670</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>ELASTIC N V</nameOfIssuer>
		<titleOfClass>ORD SHS</titleOfClass>
		<cusip>N14506104</cusip>
		<value>510</value>
		<shrsOrPrnAmt>
			<sshPrnamt>6384</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>FORTY SEVEN INC</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>34983P104</cusip>
		<value>11365</value>
		<shrsOrPrnAmt>
			<sshPrnamt>703273</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>HAWAIIAN ELEC INDUSTRIES</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>419870100</cusip>
		<value>313</value>
		<shrsOrPrnAmt>
			<sshPrnamt>7680</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>ISHARES INC</nameOfIssuer>
		<titleOfClass>CORE MSCI EMKT</titleOfClass>
		<cusip>46434G103</cusip>
		<value>187879</value>
		<shrsOrPrnAmt>
			<sshPrnamt>3633318</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>KIMBELL RTY PARTNERS LP</nameOfIssuer>
		<titleOfClass>UNIT</titleOfClass>
		<cusip>49435R102</cusip>
		<value>822</value>
		<shrsOrPrnAmt>
			<sshPrnamt>45000</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>KODIAK SCIENCES INC</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>50015M109</cusip>
		<value>4517</value>
		<shrsOrPrnAmt>
			<sshPrnamt>691767</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>LOGICBIO THERAPEUTICS INC</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>54142F102</cusip>
		<value>8984</value>
		<shrsOrPrnAmt>
			<sshPrnamt>909244</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>LYFT INC</nameOfIssuer>
		<titleOfClass>CL A COM</titleOfClass>
		<cusip>55087P104</cusip>
		<value>931</value>
		<shrsOrPrnAmt>
			<sshPrnamt>11890</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>ON DECK CAP INC</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>682163100</cusip>
		<value>65</value>
		<shrsOrPrnAmt>
			<sshPrnamt>12022</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>PRINCIPIA BIOPHARMA INC</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>74257L108</cusip>
		<value>308</value>
		<shrsOrPrnAmt>
			<sshPrnamt>9045</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>SPDR S&amp;P 500 ETF TR</nameOfIssuer>
		<titleOfClass>TR UNIT</titleOfClass>
		<cusip>78462F103</cusip>
		<value>421888</value>
		<shrsOrPrnAmt>
			<sshPrnamt>1493514</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>VANGUARD INTL EQUITY INDEX F</nameOfIssuer>
		<titleOfClass>ALLWRLD EX US</titleOfClass>
		<cusip>922042775</cusip>
		<value>2007</value>
		<shrsOrPrnAmt>
			<sshPrnamt>40016</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>VERACYTE INC</nameOfIssuer>
		<titleOfClass>COM</titleOfClass>
		<cusip>92337F107</cusip>
		<value>312</value>
		<shrsOrPrnAmt>
			<sshPrnamt>12500</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
	<infoTable>
		<nameOfIssuer>VIPER ENERGY PARTNERS LP</nameOfIssuer>
		<titleOfClass>COM UNT RP INT</titleOfClass>
		<cusip>92763M105</cusip>
		<value>829</value>
		<shrsOrPrnAmt>
			<sshPrnamt>25000</sshPrnamt>
			<sshPrnamtType>SH</sshPrnamtType>
		</shrsOrPrnAmt>
		<investmentDiscretion>SOLE</investmentDiscretion>
		<votingAuthority>
			<Sole>0</Sole>
			<Shared>0</Shared>
			<None>0</None>
		</votingAuthority>
	</infoTable>
</informationTable>
