Summary of Significant Accounting and Reporting Policies - Basis of Presentation, Ownership (Details) $ in Millions		6 Months Ended
	Jun. 30, 2020 USD ($)	Jun. 30, 2020 item
Basis of Presentation
Number of primary operating business units | item		2
Appraisal on file period to determine if reserve is required on 1-4 family residential loans		2 years
Period Delinquent Consumer Loans Written Off		90 days
Minimum
Basis of Presentation
Economic forecast variables period		1 year
Maximum
Basis of Presentation
Economic forecast variables period		4 years
NLC | Discontinued Operations, Disposed of by sale
Basis of Presentation
Cash proceeds from sale | $	$ 154.1
PPC
Basis of Presentation
Ownership percentage	100.00%	100.00%
Securities Holdings
Basis of Presentation
Ownership percentage	100.00%	100.00%
HTH Hillcrest Project LLC
Basis of Presentation
Membership ownership percentage		100.00%
Hilltop Investments I, LLC
Basis of Presentation
Membership ownership percentage		100.00%
PPC | PlainsCapital (the Bank)
Basis of Presentation
Ownership percentage	100.00%	100.00%
PPC | Hilltop Opportunity Partners LLC
Basis of Presentation
Membership ownership percentage		100.00%
PPC | PCC Statutory Trusts
Basis of Presentation
Ownership percentage	100.00%	100.00%
PlainsCapital (the Bank) | Prime Lending
Basis of Presentation
Ownership percentage	100.00%	100.00%
Prime Lending | Ventures Management
Basis of Presentation
Membership ownership percentage		100.00%
Hilltop Investments I, LLC | Hillcrest Land LLC
Basis of Presentation
Membership ownership percentage		50.00%