Condensed Parent Company Information - Condensed Statements of Income (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Income From subsidiaries
Income tax expense (benefit)	$ 66,465	$ 52,510	$ 45,613
Net income	175,722	163,356	151,742
Hancock [Member]
Operating Income From subsidiaries
Cash dividends received from bank subsidiaries	124,000	249,000	25,000
Non-cash dividend from bank subsidiary in restructuring			225,000
Dividends received from non-bank subsidiaries		2,990	150
Equity in earnings of subsidiaries greater than (less than) dividends received	58,358	(82,203)	(94,486)
Total operating income	182,358	169,787	155,664
Other (expense) income, net	(10,035)	(10,335)	(6,673)
Income tax expense (benefit)	(3,399)	(3,904)	(2,751)
Net income	$ 175,722	$ 163,356	$ 151,742