Summary of Significant Accounting and Reporting Policies - Basis of Presentation, Ownership (Details)	12 Months Ended
	Dec. 31, 2016 item
Basis of Presentation
Number of Operating Business Units	3
PPC
Basis of Presentation
Ownership percentage of subsidiary owned by the reporting entity	100.00%
PlainsCapital
Basis of Presentation
Ownership percentage of subsidiary owned by subsidiary of the reporting entity	100.00%
Plains Capital Equity LLC
Basis of Presentation
Ownership percentage of subsidiary owned by subsidiary of the reporting entity	100.00%
PrimeLending
Basis of Presentation
Ownership percentage of subsidiary owned by subsidiary of the reporting entity	100.00%
Ventures Management
Basis of Presentation
Ownership percentage of subsidiary owned by subsidiary of the reporting entity	100.00%
Ventures
Basis of Presentation
Ownership percentage of subsidiary owned by subsidiary of the reporting entity	51.00%
Mutual Of Omaha Mortgage, LLC
Basis of Presentation
Ownership percentage of subsidiary owned by subsidiary of the reporting entity	51.00%
PCC Statutory Trusts
Basis of Presentation
Ownership percentage of subsidiary owned by subsidiary of the reporting entity	100.00%
Securities Holdings
Basis of Presentation
Ownership percentage of subsidiary owned by the reporting entity	100.00%
NLC
Basis of Presentation
Ownership percentage of subsidiary owned by the reporting entity	100.00%