Condensed Parent Company Information (Condensed Statements of Cash Flows) (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 16, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Net cash provided by operating activities		$ 449,184	$ 411,085	$ 343,915
Proceeds from sales of securities available for sale		455,162	213,877	173,215
Other, net		491	(6,824)	825
Net cash used in investing activities		(846,902)	(895,321)	(1,321,031)
Proceeds from issuance of long term debt		20,610	165	6,838
Repayments of long term debt		(90,216)	(204,111)	(21,271)
Dividends paid to stockholders		(88,838)	(83,266)	(76,551)
Repurchase of common stock		(8,267)
Proceeds from issuance of common stock	$ 259,000			259,299
Payroll tax remitted on net share settlement of equity awards		(8,695)	(11,881)	(3,178)
Net cash provided by financing activities		394,142	498,495	1,045,931
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS		(3,576)	14,259	68,815
CASH AND DUE FROM BANKS, BEGINNING		386,948	372,689	303,874
CASH AND DUE FROM BANKS, ENDING		383,372	386,948	372,689
Hancock Whitney Corporation [Member]
Cash flows from operating activities - principally dividends received from subsidiaries		216,270	111,591	122,528
Net cash provided by operating activities		216,270	111,591	122,528
Contribution of capital to subsidiary			(270,000)	(21,000)
Proceeds from sales of securities available for sale		47,557
Proceeds from principal paydowns of securities available for sale		9,091	11,015	13,827
Net cash used in investing activities		56,648	(258,985)	(7,173)
Repayments of long term debt		(89,200)	(17,900)	(17,900)
Dividends paid to stockholders		(88,838)	(83,266)	(77,012)
Repurchase of common stock		(8,267)
Proceeds from issuance of common stock		4,693	15,312	262,961
Payroll tax remitted on net share settlement of equity awards		(8,695)	(11,881)	(3,178)
Other, net				(133)
Net cash provided by financing activities		(190,307)	(97,735)	164,738
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS		82,611	(245,129)	280,093
CASH AND DUE FROM BANKS, BEGINNING		71,328	316,457	36,364
CASH AND DUE FROM BANKS, ENDING		$ 153,939	$ 71,328	$ 316,457