Derivative Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Not Designated as Hedging Instrument | Prime Lending
Derivative financial instruments
Increase (decrease) in the fair value of the derivatives	$ (35,303)	$ 4,033	$ (13,251)	$ (225)
Not Designated as Hedging Instrument | Hilltop Broker-Dealers
Derivative financial instruments
Increase (decrease) in the fair value of the derivatives	10,906	6,923	9,579	(15,272)
Not Designated as Hedging Instrument | Plains Capital Bank
Derivative financial instruments
Increase (decrease) in the fair value of the derivatives	17	$ 8	46	$ 19
Not Designated as Hedging Instrument | PrimeLending and Hilltop Broker-Dealers | Other Assets
Derivative financial instruments
Cash collateral advanced to offset net derivative liability	10,500		10,500		$ 4,200
Interest Rate Lock Commitments | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	1,404,328		1,404,328		1,283,152
Estimated Fair Value	15,061		15,061		25,489
Commitments to Purchase MBSs | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	736,656		736,656		1,575,264
Estimated Fair Value	2,201		2,201		(674)
Commitments to Sell MBSs | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	2,972,796		2,972,796		3,314,173
Estimated Fair Value	(4,938)		(4,938)		(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	500		500		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	9,300		9,300
Interest rate swaps | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	46,849		46,849		68,413
Estimated Fair Value	836		836		(1,949)
Interest rate swaps | Designated as hedges
Derivative financial instruments
Available for sale securities and loans held for investment	306,100		306,100		218,000
Interest rate swaps | Cash Flow Hedging | Designated as hedges
Derivative financial instruments
Notional Amount	360,000		360,000		190,000
Estimated Fair Value	13,195		13,195		603
Interest rate swaps | Fair Value Hedging | Designated as hedges
Derivative financial instruments
Notional Amount	336,034		336,034		221,232
Estimated Fair Value	29,900		29,900		3,207
Cumulative adjustment in available for sale securities and loans held for investment	29,900		29,900		3,200
U.S. Treasury bond futures and options | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	257,900		257,900		247,800
Eurodollar and other futures | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	2,807,000		2,807,000		2,061,800
Credit default swaps | Not Designated as Hedging Instrument
Derivative financial instruments
Notional Amount	2,000		2,000		7,000
Estimated Fair Value	$ 2		$ 2		$ (15)