Earnings Per Share (Computation of Earnings Per Common Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Net income to common shareholders	$ 215,632	$ 149,296	$ 131,461
Net income allocated to participating securities - basic and diluted	4,670	3,598	2,895
Net income allocated to common shareholders - basic and diluted	$ 210,962	$ 145,698	$ 128,566
Weighted-average common shares - basic	84,695	77,850	78,197
Dilutive potential common shares	268	99	110
Weighted-average common shares - diluted	84,963	77,949	78,307
Earnings per common share: Basic	$ 2.49	$ 1.87	$ 1.64
Earnings per common share: Diluted	$ 2.48	$ 1.87	$ 1.64
Hancock Holding Company [Member]
Net income to common shareholders	$ 215,632	$ 149,296	$ 131,461