Loans Held for Investment - TDRs (Details)	3 Months Ended	6 Months Ended
Jun. 30, 2022 USD ($) loan	Jun. 30, 2021 USD ($) loan	Jun. 30, 2022 USD ($) loan	Jun. 30, 2021 USD ($) loan
TDRs, Non-covered loans
Number of TDR loans granted \| loan	2	1	3	1
TDR at extension \| $	$ 3,000,000.0	$ 700,000	$ 3,600,000	$ 700,000
TDR modifications, end of period \| $			3,100,000
Unadvanced commitments to borrowers \| $	$ 0		$ 0
Number of TDRs granted in preceding twelve months for which payment was at least 30 days past due \| loan			0	0
AB Note \| Minimum \| Plains Capital Bank
TDRs, Non-covered loans
Number of loans into which a single loan may be reconfigured \| loan			2

Represents the number of loans into which a single loan may be reconfigured under the modification.

No definition available.

Name:	hth_FinancingReceivableNumberOfLoansIntoWhichSingleLoanIsReconfigured
Namespace Prefix:	hth_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Represents the amount of unadvanced commitments to borrowers whose loans have been restructured in troubled debt restructurings.

+ References

No definition available.

+ Details

Name:	hth_FinancingReceivablesImpairedTroubledDebtRestructuringUnadvancedCommitments
Namespace Prefix:	hth_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancingReceivableModificationsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of financing receivables that have been modified by troubled debt restructurings.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 33
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953676-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsNumberOfContracts2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount, after troubled debt restructuring, of modified financing receivable.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, before troubled debt restructuring, of financing receivable to be modified.

+ References

+ Details

Name:	us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Number of financing receivable contracts modified as troubled debt restructuring within previous 12 months, with subsequent payment default.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI https://asc.fasb.org/extlink&oid=123577603&loc=SL6953682-111524

+ Details

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_LoanRestructuringModificationAxis=hth_ABNoteMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=hth_PlainsCapitalBankMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: