Stockholders' Equity (Compliance with Regulatory Capital Requirements) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Tier 1 leverage capital, Actual, Amount	$ 2,584,162	$ 2,391,762
Common equity tier 1 (to risk weighted assets), Actual, Amount	2,584,162	2,391,762
Tier 1 capital (to risk weighted assets), Actual, Amount	2,584,162	2,391,762
Total capital (to risk weighted assets), Actual, Amount	$ 2,929,387	$ 2,736,276
Tier 1 leverage capital, Actual, Ratio %	8.76%	8.67%
Common equity tier 1 (to risk weighted assets), Actual, Ratio %	10.50%	10.48%
Tier 1 capital (to risk weighted assets), Actual, Ratio %	10.50%	10.48%
Total capital (to risk weighted assets), Actual, Ratio %	11.90%	11.99%
Tier 1 leverage capital, Required for Minimum Capital Adequacy, Amount	$ 1,180,163	$ 1,103,544
Common equity tier 1 (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	1,107,527	1,026,637
Tier 1 capital (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	1,476,702	1,368,849
Total capital (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	$ 1,968,936	$ 1,825,132
Tier 1 leverage capital, Required for Minimum Capital Adequacy, Ratio %	4.00%	4.00%
Common equity tier 1 (to risk weighted assets), Required for Minimum Capital Adequacy, Ratio %	4.50%	4.50%
Tier 1 capital (to risk weighted assets), Required for Minimum Capital Adequacy, Ratio %	6.00%	6.00%
Total capital (to risk weighted assets), Required for Minimum Capital Adequacy, Ratio %	8.00%	8.00%
Tier 1 leverage capital, Required To Be Well Capitalized, Amount	$ 1,475,204	$ 1,379,430
Common equity tier 1 (to risk weighted assets), Required To Be Well Capitalized, Amount	1,599,761	1,482,920
Tier 1 capital (to risk weighted assets), Required To Be Well Capitalized, Amount	1,968,936	1,825,132
Total capital (to risk weighted assets), Required To Be Well Capitalized, Amount	$ 2,461,171	$ 2,281,415
Tier 1 leverage capital, Required To Be Well Capitalized, Ratio %	5.00%	5.00%
Common equity tier 1 (to risk weighted assets), Required To Be Well Capitalized, Ratio %	6.50%	6.50%
Tier 1 capital (to risk weighted assets), Required To Be Well Capitalized, Ratio %	8.00%	8.00%
Total capital (to risk weighted assets), Required To Be Well Capitalized, Ratio %	10.00%	10.00%
Hancock Whitney Bank [Member]
Tier 1 leverage capital, Actual, Amount	$ 2,640,913	$ 2,351,090
Common equity tier 1 (to risk weighted assets), Actual, Amount	2,640,913	2,351,090
Tier 1 capital (to risk weighted assets), Actual, Amount	2,640,913	2,351,090
Total capital (to risk weighted assets), Actual, Amount	$ 2,836,138	$ 2,545,604
Tier 1 leverage capital, Actual, Ratio %	8.96%	8.54%
Common equity tier 1 (to risk weighted assets), Actual, Ratio %	10.74%	10.32%
Tier 1 capital (to risk weighted assets), Actual, Ratio %	10.74%	10.32%
Total capital (to risk weighted assets), Actual, Ratio %	11.53%	11.17%
Tier 1 leverage capital, Required for Minimum Capital Adequacy, Amount	$ 1,179,194	$ 1,101,372
Common equity tier 1 (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	1,106,558	1,025,355
Tier 1 capital (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	1,475,411	1,367,140
Total capital (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	$ 1,967,214	$ 1,822,053
Tier 1 leverage capital, Required for Minimum Capital Adequacy, Ratio %	4.00%	4.00%
Common equity tier 1 (to risk weighted assets), Required for Minimum Capital Adequacy, Ratio %	4.50%	4.50%
Tier 1 capital (to risk weighted assets), Required for Minimum Capital Adequacy, Ratio %	6.00%	6.00%
Total capital (to risk weighted assets), Required for Minimum Capital Adequacy, Ratio %	8.00%	8.00%
Tier 1 leverage capital, Required To Be Well Capitalized, Amount	$ 1,473,992	$ 1,376,715
Common equity tier 1 (to risk weighted assets), Required To Be Well Capitalized, Amount	1,598,362	1,481,068
Tier 1 capital (to risk weighted assets), Required To Be Well Capitalized, Amount	1,967,214	1,822,853
Total capital (to risk weighted assets), Required To Be Well Capitalized, Amount	$ 2,459,018	$ 2,278,566
Tier 1 leverage capital, Required To Be Well Capitalized, Ratio %	5.00%	5.00%
Common equity tier 1 (to risk weighted assets), Required To Be Well Capitalized, Ratio %	6.50%	6.50%
Tier 1 capital (to risk weighted assets), Required To Be Well Capitalized, Ratio %	8.00%	8.00%
Total capital (to risk weighted assets), Required To Be Well Capitalized, Ratio %	10.00%	10.00%

Common Equity Tier One Risk Based Capital

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Common Equity Tier One Risk Based Capital Required For Capital Adequacy To Risk Weighted Assets

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Common equity tier one risk based capital required to be well capitalized.

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Common Equity Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets

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Common Equity Tier One Risk Based Capital To Risk Weighted Assets

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The amount of total capital as defined in the regulations.

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The minimum amount of Total Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The minimum Total risk based capital ratio (total capital divided by risk weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.

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The amount of Total Capital required to be categorized as well as capitalized under the regulatory framework for prompt corrective action.

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The Total risk based capital ratio (total capital divided by risk weighted assets) required to be categorized as "well capitalized", in the regulatory framework for prompt corrective action.

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Total Capital divided by risk weighted assets as defined in the regulations.

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Tier 1 Leverage Capital as defined in the regulations. Also called Core Capital.

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The amount of Tier 1 Leverage Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.

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Tier 1 Risk Based Capital as defined in the regulations.

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Tier 1 capital divided by risk weighted assets as defined by regulations.

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