Condensed Parent Company Information - Condensed Balance Sheets (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Assets:
Securities available for sale	$ 2,048,442	$ 4,496,900
Total assets	19,464,485	19,774,096	8,138,327
Liabilities and Stockholders' Equity:
Long term debt	396,589	353,890
Stockholders' equity	2,453,278	2,367,163	856,548	837,663
Total liabilities and stockholders' equity	19,464,485	19,774,096
Hancock [Member]
Assets:
Cash	26,041	28,015
Securities available for sale	132,551	103,788
Investment in bank subsidiaries	2,495,412	2,358,368
Investment in non-bank subsidiaries	8,071	10,222
Due from subsidiaries and other assets	13,447	9,014
Total assets	2,675,522	2,509,407
Liabilities and Stockholders' Equity:
Long term debt	220,000	140,000
Due to subsidiaries and other liabilities	2,244	2,244
Stockholders' equity	2,453,278	2,367,163
Total liabilities and stockholders' equity	$ 2,675,522	$ 2,509,407