Acquisition - Identifiable Assets Acquired and Liabilities Assumed (Details) $ in Thousands				4 Months Ended	12 Months Ended
	Jan. 01, 2015 USD ($)	Sep. 13, 2013 USD ($) item	Sep. 13, 2013 USD ($)	Dec. 31, 2013 USD ($) item	Dec. 31, 2015 USD ($)	Dec. 31, 2013 USD ($)
Fair values of the identifiable assets acquired, and liabilities assumed
Bargain purchase gain					$ (81,289)	$ (12,585)
SWS
Fair values of the identifiable assets acquired, and liabilities assumed
Cash and due from banks	$ 119,314
Federal funds sold and securities purchased under agreements to resell	44,741
Assets segregated for regulatory purposes	181,610
Securities	707,476
Loans	863,819
Other assets	159,906
Broker-dealer and clearing organization receivables	1,221,793
Total identifiable assets acquired	3,298,659
Deposits	(1,287,509)
Broker-dealer and clearing organization payables	(1,109,978)
Short-term borrowings	(164,240)
Securities sold, not yet purchased, at fair value	(140,409)
Notes payable	(76,643)
Other liabilities	(89,466)
Total liabilities assumed	(2,868,245)
Bargain purchase gain	(81,289)
Net identifiable assets acquired	349,125
Less Hilltop existing investment in SWS	(70,282)
Net identifiable assets acquired	278,843
Tax on bargain purchase gain	0
Allocation to intangible assets
Gross Intangible Assets	$ 7,460
FNB
Fair values of the identifiable assets acquired, and liabilities assumed
Cash and due from banks		$ 362,695	$ 362,695
Securities		286,214	286,214
Premises and equipment		78,399	78,399
FDIC indemnification asset		185,680	185,680
Other assets		26,300	26,300
Other intangible assets		4,270	4,270
Total identifiable assets acquired		2,238,212	2,238,212
Deposits		(2,211,740)	(2,211,740)
Other liabilities		(13,887)	(13,887)
Total liabilities assumed		(2,225,627)	(2,225,627)
Bargain purchase gain				$ (12,600)
Net identifiable assets acquired		12,585	12,585
Net interest income				32,000
Other revenues				20,400
Net income				18,500
Tax on bargain purchase gain				$ 4,500
FNB | Noncovered
Fair values of the identifiable assets acquired, and liabilities assumed
Loans		42,884	42,884
FNB | Covered
Fair values of the identifiable assets acquired, and liabilities assumed
Loans		1,116,583	1,116,583
Other real estate owned		135,187	135,187
Bank | FNB
Fair values of the identifiable assets acquired, and liabilities assumed
Loans		$ 1,200,000	$ 1,200,000
Number of properties purchased from the FDIC | item		44
Aggregate purchase price of properties purchased from the FDIC		$ 59,500
Number of additional properties purchased pursuant to exercise of option from the FDIC | item				7
Aggregate purchase price of additional properties purchased pursuant to exercise of option from the FDIC				$ 4,900
Exercise of right to purchase furniture and equipment				$ 10,300
Percentage of losses to be absorbed by FDIC on the first $240.4 million of losses incurred as per the loss sharing agreement		80.00%
Threshold amount of losses incurred for 80% of losses to be absorbed by FDIC as per the loss sharing agreement, first layer		$ 240,400
Percentage of losses to be absorbed by FDIC in excess of $240.4 million up to and including $365.7 million of losses incurred as per the loss sharing agreement		0.00%
Threshold amount of losses incurred for 0% of losses to be absorbed by FDIC as per the loss sharing agreement, second layer		$ 365,700
Percentage of losses to be absorbed by FDIC in excess of $365.7 million of losses incurred as per the loss sharing agreement		80.00%
Period for which payment is required to be made to the FDIC of true-up amount			10 years
Bank | FNB | Covered | Commercial loan
Fair values of the identifiable assets acquired, and liabilities assumed
Period of loss-sharing agreements in effect			5 years
Period of loss recovery provisions in effect			8 years
Bank | FNB | Covered | Single family residential loans
Fair values of the identifiable assets acquired, and liabilities assumed
Period of loss-sharing agreements in effect			10 years
Period of loss recovery provisions in effect			10 years
Fair value adjustments | FNB
Fair values of the identifiable assets acquired, and liabilities assumed
Cost basis net assets		$ 215,000	$ 215,000
Cash payment received from the FDIC		45,000
Securities		(3,341)	(3,341)
Loans		(343,068)	(343,068)
Premises and equipment		3,565	3,565
Other real estate owned		(79,273)	(79,273)
FDIC indemnification asset		185,680	185,680
Other intangible assets		4,270	4,270
Deposits		(8,282)	(8,282)
Other liabilities		(6,966)	(6,966)
Net identifiable assets acquired		$ 12,585	$ 12,585
Customer Relationships | SWS
Allocation to intangible assets
Estimated Useful Life	14 years
Gross Intangible Assets	$ 7,300
Core deposits | SWS
Allocation to intangible assets
Estimated Useful Life	4 years
Gross Intangible Assets	$ 160