The average effective interest rate during the reporting period.

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Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Fair value portion of short term borrowing where a bank borrows, at the federal funds rate, from another bank and securities that an entity sells and agrees to repurchase at a specified date for a specified price.

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Amount after offset of short term borrowing where a bank borrows, at the federal funds rate, from another bank and securities that an entity sells and agrees to repurchase at a specified date for a specified price.

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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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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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Weighted average interest rate of short-term debt outstanding calculated at point in time.

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For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period.

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Short-term Borrowings (Details) - USD ($) $ in Thousands	3 Months Ended
Short-term Borrowings (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017	Dec. 31, 2017
Short-term borrowings
Short-term borrowings	$ 1,064,325		$ 1,206,424
Hilltop Broker-Dealers
Short-term borrowings
Weighted average interest rate (as a percent)	2.59%		2.27%
Federal funds purchased.
Short-term borrowings
Short-term borrowings	$ 102,575		$ 101,775
Securities sold under agreement to repurchase.
Short-term borrowings
Short-term borrowings	616,750		539,149
FHLB notes
Short-term borrowings
Short-term borrowings			$ 250,000
Average balance during the year	$ 26,111	$ 180,000
Average interest rate during the year	2.03%	0.61%
Average interest rate at end of year (as a percent)	0.00%		1.30%
FHLB notes \| Maximum
Short-term borrowings
Maturity term of debt	365 days
Short-term bank loans.
Short-term borrowings
Short-term borrowings	$ 345,000		$ 315,500
Federal funds purchased and securities sold under agreements to repurchase.
Short-term borrowings
Average balance during the year	$ 678,723	$ 386,624
Average interest rate during the year	1.50%	0.76%
Average interest rate at end of year (as a percent)	1.39%		1.21%
Carrying value	$ 629,999		$ 581,636
Estimated fair value	$ 652,535		$ 598,300