Short-term Borrowings (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Short-term borrowings
Short-term borrowings	$ 1,477,201		$ 1,417,289
Hilltop Broker-Dealers
Short-term borrowings
Weighted average interest rate (as a percent)	2.08%		1.59%
Federal funds purchased.
Short-term borrowings
Short-term borrowings	$ 72,000		$ 87,125
Securities sold under agreement to repurchase.
Short-term borrowings
Short-term borrowings	611,701		195,164
FHLB notes
Short-term borrowings
Short-term borrowings	650,000		$ 1,000,000
Average balance during the period	$ 435,531	$ 303,011
Average interest rate during the period (as a percent)	1.05%	0.45%
Average interest rate at end of period (as a percent)	1.22%		0.55%
FHLB notes | Maximum
Short-term borrowings
Maturity term of debt	365 days
Short-term bank loans.
Short-term borrowings
Short-term borrowings	$ 143,500		$ 135,000
Federal funds purchased and securities sold under agreements to repurchase.
Short-term borrowings
Average balance during the period	$ 549,425	$ 351,430
Average interest rate during the period (as a percent)	0.98%	0.55%
Average interest rate at end of period (as a percent)	1.10%		0.42%
Carrying value	$ 621,429		$ 209,877
Estimated fair value	$ 648,517		$ 206,641