Stockholders' Equity (Compliance with Regulatory Capital Requirements) (Details) $ in Thousands	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2018
Tier 1 leverage capital, Actual, Amount	$ 2,890,770	$ 2,534,049
Common equity tier 1 (to risk weighted assets), Actual, Amount	2,890,770	2,534,049
Tier 1 capital (to risk weighted assets), Actual, Amount	2,890,770	2,534,049
Total capital (to risk weighted assets), Actual, Amount	$ 3,345,387	$ 3,155,692
Tier 1 leverage capital, Actual, Ratio %	8.25	7.88
Common equity tier 1 (to risk weighted assets), Actual, Ratio %	11.09%	10.61%
Tier 1 capital (to risk weighted assets), Actual, Ratio %	11.09	10.61
Total capital (to risk weighted assets), Actual, Ratio %	12.84	13.22
Tier 1 leverage capital, Required for Minimum Capital Adequacy, Amount	$ 1,402,223	$ 1,287,103
Common equity tier 1 (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	1,172,563	1,074,272
Tier 1 capital (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	1,563,417	1,432,362
Total capital (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	$ 2,084,557	$ 1,909,817
Tier 1 leverage capital, Required for Minimum Capital Adequacy, Ratio %	4.00	4.00	0.040
Common equity tier 1 (to risk weighted assets), Required for Minimum Capital Adequacy, Ratio %	4.50%	4.50%	4.50%
Tier 1 capital (to risk weighted assets), Required for Minimum Capital Adequacy, Ratio %	6.00	6.00	0.060
Total capital (to risk weighted assets), Required for Minimum Capital Adequacy, Ratio %	8.00	8.00	0.080
Tier 1 leverage capital, Required To Be Well Capitalized, Amount	$ 1,752,779	$ 1,608,878
Common equity tier 1 (to risk weighted assets), Required To Be Well Capitalized, Amount	1,693,702	1,551,726
Tier 1 capital (to risk weighted assets), Required To Be Well Capitalized, Amount	2,084,557	1,909,817
Total capital (to risk weighted assets), Required To Be Well Capitalized, Amount	$ 2,605,696	$ 2,387,271
Tier 1 leverage capital, Required To Be Well Capitalized, Ratio %	5.00	5.00	5.0
Common equity tier 1 (to risk weighted assets), Required To Be Well Capitalized, Ratio %	6.50%	6.50%	6.50%
Tier 1 capital (to risk weighted assets), Required To Be Well Capitalized, Ratio %	8.00	8.00	8.0
Total capital (to risk weighted assets), Required To Be Well Capitalized, Ratio %	10.00	10.00	10.0
Hancock Whitney Bank [Member]
Tier 1 leverage capital, Actual, Amount	$ 2,926,874	$ 2,607,215
Common equity tier 1 (to risk weighted assets), Actual, Amount	2,926,874	2,607,215
Tier 1 capital (to risk weighted assets), Actual, Amount	2,926,874	2,607,215
Total capital (to risk weighted assets), Actual, Amount	$ 3,208,991	$ 2,905,988
Tier 1 leverage capital, Actual, Ratio %	8.36	8.11
Common equity tier 1 (to risk weighted assets), Actual, Ratio %	11.24%	10.94%
Tier 1 capital (to risk weighted assets), Actual, Ratio %	11.24	10.94
Total capital (to risk weighted assets), Actual, Ratio %	12.33	12.19
Tier 1 leverage capital, Required for Minimum Capital Adequacy, Amount	$ 1,401,157	$ 1,286,059
Common equity tier 1 (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	1,171,341	1,072,924
Tier 1 capital (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	1,561,788	1,430,565
Total capital (to risk weighted assets), Required for Minimum Capital Adequacy, Amount	$ 2,082,384	$ 1,907,420
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	$ 1,751,447	$ 1,607,573
Common equity tier 1 (to risk weighted assets), Required To Be Well Capitalized, Amount	1,691,937	1,549,778
Tier 1 capital (to risk weighted assets), Required To Be Well Capitalized, Amount	2,082,384	1,907,420
Total capital (to risk weighted assets), Required To Be Well Capitalized, Amount	$ 2,602,980	$ 2,384,275
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