Condensed Parent Company Information (Condensed Statements of Cash Flows) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net cash provided by operating activities	$ 351,949	$ 449,184	$ 411,085
Proceeds from sale of securities available for sale	268,413	455,162	213,877
Other, net	(65,597)	551	(4,971)
Net cash used in investing activities	(459,022)	(846,902)	(895,321)
Repayment of long term debt	(14,222)	(90,216)	(204,111)
Dividends paid to stockholders	(94,871)	(88,838)	(83,266)
Repurchase of common stock	(185,000)	(8,267)
Payroll tax remitted on net share settlement of equity awards	(6,295)	(8,695)	(11,881)
Net cash provided by financing activities	155,805	394,142	498,495
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	48,732	(3,576)	14,259
CASH AND DUE FROM BANKS, BEGINNING	383,372	386,948	372,689
CASH AND DUE FROM BANKS, ENDING	432,104	383,372	386,948
Hancock Whitney Corporation [Member]
Cash flows from operating activities - principally dividends received from subsidiaries	255,322	216,270	111,591
Net cash provided by operating activities	255,322	216,270	111,591
Contribution of capital to subsidiary	(50,000)		(270,000)
Net cash received in acquisition	38,505
Proceeds from sale of securities available for sale		47,557
Proceeds from principal paydowns of securities available for sale		9,091	11,015
Other, net	(1,874)
Net cash used in investing activities	(13,369)	56,648	(258,985)
Repayment of long term debt	(13,919)	(89,200)	(17,900)
Dividends paid to stockholders	(94,871)	(88,838)	(83,266)
Repurchase of common stock		(8,267)
Proceeds from issuance of common stock	4,265	4,693	15,312
Payroll tax remitted on net share settlement of equity awards	(6,295)	(8,695)	(11,881)
Payment accelerated share repurchase agreement	(185,000)
Other, net	(42,129)
Net cash provided by financing activities	(337,949)	(190,307)	(97,735)
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS	(95,996)	82,611	(245,129)
CASH AND DUE FROM BANKS, BEGINNING	153,939	71,328	316,457
CASH AND DUE FROM BANKS, ENDING	$ 57,943	$ 153,939	$ 71,328

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