LIMITED POWER OF ATTORNEY FOR
SECTION 16 REPORTING OBLIGATIONS

Know all by these presents, that, effective as of June 30, 2020, the undersigned
hereby constitutes and appoints each of Len E. Williams, Mark K. Olson, Adelaide
Maudsley, and the Company's Chief Compliance Officer, signing singly, the
undersigned's true and lawful attorneys in fact, to: (1) prepare, execute in the
undersigned's name and on the undersigned's behalf, and submit to the U.S.
Securities and Exchange Commission (the "SEC") a Form ID, including amendments
thereto, and any other documents necessary or appropriate to obtain codes and
passwords enabling the undersigned to make electronic filings with the SEC of
reports required by Section 16(a) of the Securities Exchange Act of 1934 or any
rule or regulation of the SEC; (2) execute for and on behalf of the undersigned,
in the undersigned's capacity as an executive officer and/or director of
Altabancorp (formerly known as People's Utah Bancorp) (the "Company"), Forms 3,
4, and 5 in accordance with Section 16(a) of the Securities Exchange Act of 1934
and the rules thereunder, and any other forms or reports the undersigned may be
required to file in connection with the undersigned's ownership, acquisition, or
disposition of securities of the Company; (3) do and perform any and all acts
for and on behalf of the undersigned which may be necessary or desirable to
complete and execute any such Form 3, 4, or 5, or other form or report, and
timely file such form or report with the SEC and any stock exchange or similar
authority; and (4) take any other action of any type whatsoever in connection
with the foregoing which, in the opinion of such attorney in fact, may be of
benefit to, in the best interest of, or legally required by, the undersigned, it
being understood that the documents executed by such attorney in fact on behalf
of the undersigned pursuant to this Power of Attorney shall be in such form and
shall contain such terms and conditions as such attorney in fact may approve in
such attorney in fact's discretion. The undersigned hereby grants to each such
attorney in fact full power and authority to do and perform any and every act
and thing whatsoever requisite, necessary, or proper to be done in the exercise
of any of the rights and powers herein granted, as fully to all intents and
purposes as the undersigned might or could do if personally present, with full
power of substitution or revocation, hereby ratifying and confirming all that
such attorney in fact, or such attorney in fact's substitute or substitutes,
shall lawfully do or cause to be done by virtue of this power of attorney and
the rights and powers herein granted. The undersigned acknowledges that the
foregoing attorneys in fact, in serving in such capacity at the request of the
undersigned, are not assuming, nor is the Company assuming, any of the
undersigned's responsibilities to comply with Section 16 of the Securities
Exchange Act of 1934. This Power of Attorney supersedes in its entirety any form
of power of attorney previously executed by the undersigned relating to SEC
reporting of the undersigned's holdings in the Company and shall remain in full
force and effect until the undersigned is no longer required to file Forms 3, 4,
and 5 with respect to the undersigned's holdings of and transactions in
securities issued by the Company, unless earlier revoked by the undersigned in a
signed writing delivered to the foregoing attorneys in fact. IN WITNESS WHEREOF,
the undersigned has caused this Power of Attorney to be executed as of the date
set forth below and to be effective as of the date specified above.