Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Article 12
-Section 13
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Fair value of the assets less the liabilities of a derivative or group of derivatives.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
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Reference 2: http://www.xbrl.org/2003/role/presentationRef
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Amount of increase (decrease) in the fair value of derivatives recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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- Definition

Amount of right to receive cash collateral under master netting arrangements offset against derivative liabilities.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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-Name Accounting Standards Codification
-Topic 210
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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.

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No definition available.

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Derivative Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Not Designated as Hedging Instrument \| PrimeLending
Derivative financial instruments
Net gain (loss) due to changes in the fair value of the derivative instruments	$ 2,200	$ (9,900)	$ 9,000	$ (400)
Not Designated as Hedging Instrument \| Hilltop Broker-Dealers
Derivative financial instruments
Net gain (loss) due to changes in the fair value of the derivative instruments	3,600	$ (3,600)	1,400	12,600
Not Designated as Hedging Instrument \| PlainsCapital (the Bank)
Derivative financial instruments
Net gain (loss) due to changes in the fair value of the derivative instruments			100	$ 200
Interest Rate Lock Commitments
Derivative financial instruments
Notional Amount	1,023,165		1,023,165		$ 850,850
Estimated Fair Value	20,427		20,427		18,851
Customer-based written options
Derivative financial instruments
Notional Amount	31,200		31,200		21,637
Estimated Fair Value	(122)		(122)		38
Customer-based purchased options
Derivative financial instruments
Notional Amount	31,200		31,200		21,637
Estimated Fair Value	122		122		(38)
Commitments to Purchase MBSs
Derivative financial instruments
Notional Amount	2,832,755		2,832,755		2,831,635
Estimated Fair Value	2,172		2,172		(921)
Commitments to Sell MBSs
Derivative financial instruments
Notional Amount	4,858,032		4,858,032		4,963,498
Estimated Fair Value	7,894		7,894		2,972
Commitments to Sell MBSs \| PrimeLending
Derivative financial instruments
Cash collateral advanced to offset net derivative liability	8,400		8,400		800
Interest rate swaps
Derivative financial instruments
Notional Amount	22,780		22,780		25,971
Estimated Fair Value	195		195		51
U.S. Treasury bond futures and options
Derivative financial instruments
Notional Amount	242,900		242,900		214,500
Eurodollar futures
Derivative financial instruments
Notional Amount	696,000		696,000
Treasury bond futures and options and Eurodollar futures \| PrimeLending and Hilltop Broker-Dealers
Derivative financial instruments
Cash collateral advanced to offset net derivative liability	$ 2,300		$ 2,300		$ 3,200