Derivative Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021	Dec. 31, 2021
Not Designated as Hedging Instrument | Prime Lending
Derivative financial instruments
Increase (decrease) in the fair value of the derivatives	$ 2,276	$ 780	$ (10,975)	$ 555
Not Designated as Hedging Instrument | Hilltop Broker-Dealers
Derivative financial instruments
Increase (decrease) in the fair value of the derivatives	14,240	11,427	23,819	(3,845)
Not Designated as Hedging Instrument | Plains Capital Bank
Derivative financial instruments
Increase (decrease) in the fair value of the derivatives	7	$ 7	53	$ 26
Not Designated as Hedging Instrument | PrimeLending and Hilltop Broker-Dealers | Other Assets
Derivative financial instruments
Cash collateral advanced to offset net derivative liability	11,700		11,700		$ 4,200
Interest Rate Lock Commitments | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	1,131,664		1,131,664		1,283,152
Estimated Fair Value	(16,729)		(16,729)		25,489
Commitments to Purchase MBSs | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	1,353,969		1,353,969		1,575,264
Estimated Fair Value	(27,946)		(27,946)		(674)
Commitments to Sell MBSs | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	3,150,790		3,150,790		3,314,173
Estimated Fair Value	71,201		71,201		(355)
Commitments to Sell MBSs | Not Designated as Hedging Instrument | Prime Lending | Other Assets
Derivative financial instruments
Cash collateral advanced to offset net derivative liability	100		100		100
Commitments to Sell MBSs | Not Designated as Hedging Instrument | Prime Lending | Other Liabilities
Derivative financial instruments
Cash collateral advanced to offset net derivative assets	56,300		56,300
Interest rate swaps | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	36,317		36,317		68,413
Estimated Fair Value	2,976		2,976		(1,949)
Interest rate swaps | Designated as hedges
Derivative financial instruments
Available for sale securities and loans held for investment	296,000		296,000		218,000
Interest rate swaps | Cash Flow Hedging | Designated as hedges
Derivative financial instruments
Notional Amount	415,000		415,000		190,000
Estimated Fair Value	22,675		22,675		603
Interest rate swaps | Fair Value Hedging | Designated as hedges
Derivative financial instruments
Notional Amount	340,323		340,323		221,232
Estimated Fair Value	44,322		44,322		3,207
Cumulative adjustment in available for sale securities and loans held for investment	44,300		44,300		3,200
U.S. Treasury bond futures and options | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	274,000		274,000		247,800
Eurodollar and other futures | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	2,964,000		2,964,000		2,061,800
Credit default swaps | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	1,000		1,000		7,000
Estimated Fair Value	$ 5		$ 5		$ (15)