Condensed Parent Company Information (Condensed Statements of Cash Flows) (Details) - USD ($) $ in Thousands		12 Months Ended
	Dec. 16, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net cash provided by operating activities		$ 340,737	$ 232,345	$ 352,428
Proceeds from principal paydowns of securities available for sale		173,215	9,289	1,455
Other, net		825	(3,604)	10,101
Net cash used in investing activities		(1,321,031)	(2,276,431)	(1,910,459)
Proceeds from issuance of long term debt		6,838	273,565	21,000
Repayments of long-term debt		(21,271)	(157,933)	(35,360)
Dividends paid to stockholders		(76,551)	(77,013)	(80,392)
Repurchase of common stock			(95,613)	(47,618)
Proceeds from issuance of common stock	$ 259,000	259,299
Net cash provided by financing activities		1,049,109	1,991,505	1,566,046
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS		68,815	(52,581)	8,015
CASH AND DUE FROM BANKS, BEGINNING		303,874	356,455	348,440
CASH AND DUE FROM BANKS, ENDING		372,689	303,874	356,455
Hancock [Member]
Cash flows from operating activities - principally dividends received from subsidiaries		119,350	30,527	126,491
Net cash provided by operating activities		119,350	30,527	126,491
Contribution of capital to subsidiary		(21,000)	(90)
Proceeds from principal paydowns of securities available for sale		13,827	12,863	12,664
Other, net			1,629
Net cash used in investing activities		(7,173)	14,402	12,664
Proceeds from issuance of long term debt			269,004
Repayments of long-term debt		(17,900)	(149,600)	(35,200)
Dividends paid to stockholders		(77,012)	(77,474)	(80,392)
Repurchase of common stock			(95,613)	(47,618)
Proceeds from issuance of common stock		262,961	347	2,488
Other, net		(133)
Net cash provided by financing activities		167,916	(53,336)	(160,722)
NET INCREASE (DECREASE) IN CASH AND DUE FROM BANKS		280,093	(8,407)	(21,567)
CASH AND DUE FROM BANKS, BEGINNING		36,364	44,771	66,338
CASH AND DUE FROM BANKS, ENDING		$ 316,457	$ 36,364	$ 44,771